Answer:
Step-by-step explanation:
Hello!
The objective is to test if the proportion of "X: gloves fitness, categorized: Fit poorly and Fit well" is the same for two populations of interest, "male firefighters" and "female firefighters"
To do this you have to conduct a Chi-Square test of Homogeneity.
In the null hypothesis you have to state that the proportion of the categories of the variable are the same for all the populations of interest.
Be
M: the firefighter is male
F: the firefighter is female
Y: represents the category that the gloves "fit poorly"
W: represents the category that the gloves "fit well"
The null hypothesis will be:
H₀: P(Y|M)=P(Y|F)=P(Y)
P(W|M)=P(W|F)=P(W)
H₁: At least one of the statements in the null hypothesis is false.
α: 0.01
To calculate the statistic under the null hypothesis you have to calculate the expected frequencies first:
[tex]E_{ij}= O_{.j}*\frac{O_{i.}}{n}[/tex]
O.j= total of the j-column
Oi.= total of the i-row
n= total of observations
[tex]E_{11}= 547*\frac{152}{586} = 141.88[/tex]
[tex]E_{12}=39*\frac{152}{586}= 10.12[/tex]
[tex]E_{21}= 547*\frac{434}{586} = 405.12[/tex]
[tex]E_{22}= 39*\frac{434}{586} = 28.88[/tex]
[tex]X^2= sum \frac{(O_{ij}-E_{ij})^2}{E_{ij}} ~~~X^2_{(r-1)(c-1)}[/tex]
r= number of rows (in this case 2)
c=number of columns (in this case 2)
[tex]X^2_{H_0}= \frac{(132-141.88)^2}{141.88} +\frac{(20-10.12)^2}{10.12} +\frac{(415-405.12)^2}{405.12} +\frac{(19-28.88)^2}{28.88} = 13.95[/tex]
Using the critical value approach, you have to remember that this test is always one-tailed to the right, meaning that you'll have only one critical value from which the rejection region is defined:
[tex]X^2_{(r-1)(c-1);1-\alpha }= X^2_{1;0.99}= 6.635[/tex]
The decision rule is then:
If [tex]X^2_{H_0}[/tex] ≥ 6.635, reject the null hypothesis.
If [tex]X^2_{H_0}[/tex] < 6.635, do not reject the null hypothesis.
The calculated value is greater than the critical value, the decision is to reject the null hypothesis.
So at a 1% level you can conclude that this test is significant. This means that the proportions of gloves fitness, categorized in "Fit poorly" and "Fit well" are different for the male and female firefighters populations.
I hope this helps!
Answer:
The Chi - Square Test Statistics is 13.98
p-value = 0.0002
CONCLUSION: Since the p-value is less than the level of significance ; (i.e p-value < ∝) we reject the null hypothesis and accept the alternative hypothesis.
Thus; there is a difference in the population proportion of glove fitness for the two genders.
Step-by-step explanation:
From the information given ; the structure of the table can be well represented as follows;
Observed data Males Females Total
Gloves fit poorly 132 20 152
Gloves fit well 415 19 434
Total 547 39 586
Expected data Males Females Total
Gloves fit poorly
Gloves fit well
Total
The objective of this question is to use the chi-square test to determine if there is a difference in the population proportion of glove fitness for the two genders.
We call represent the hypothesis as follows:
The null hypothesis: [tex]H_o:[/tex] states that there is no difference in the population proportion of glove fitness for the two genders.
The alternative hypothesis: [tex]H_a[/tex] states that there is difference in the population proportion of glove fitness for the two genders.
The expected frequency of a particular cell can be calculated by multiplying the sum of the rows and columns together, then dividing it by the Total sum
For row 1 column 1 (gloves fit poorly (male) ; we have:
[tex]= \dfrac{547*152}{586} =141.884\\[/tex]
For row 2 column 1 (gloves fit well(male) ; we have:
[tex]= \dfrac{547*434}{586} =405.116[/tex]
For row 1 column 2 (gloves fit poorly (female)) ; we have:
[tex]= \dfrac{39*152}{586} =10.116[/tex]
For row 2 column 2 ( gloves fit well ( female ) ; we have:
[tex]= \dfrac{39*434}{586} =28.884[/tex]
Thus; we can have the complete table to now be:
Observed data Males Females Total
Gloves fit poorly 132 20 152
Gloves fit well 415 19 434
Total 547 39 586
Expected data Males Females Total
Gloves fit poorly 141.884 10.116 152
Gloves fit well 405.116 28.884 434
Total 547 39 586
The Chi - Square Test Statistics can be calculated via the formula:
[tex]X^2 = \dfrac{\sum (f_o-f_e)^2}{f_e}[/tex]
where;
[tex]f_o[/tex] = observed data frequency
[tex]f_e[/tex] = expected data frequency
∴
The Chi - Square Test Statistics is as follows:
[tex]=\dfrac{(131-141.884)^2}{141.884} + \dfrac{(20-10.116)^2}{10.116}+ \dfrac{(415-405.116)^2}{405.116}+ \dfrac{(39-28.884)^2}{28.884}[/tex]
= 0.68+9.6+0.2+3.5
= 13.98
We are given the level of significance ∝ to be = 0.01
numbers of rows = 2; number of column = 2
Thus; the degree of freedom = (2-1)(2-1) = 1×1 = 1
Using the Excel Function : [ = CHISQ.DIST.RT²(X²,df)]
p-value = 0.0002
CONCLUSION: Since the p-value is less than the level of significance ; (i.e p-value < ∝) we reject the null hypothesis and accept the alternative hypothesis.
Thus; there is a difference in the population proportion of glove fitness for the two genders.
Please help I'm Timed Will Name Brainliest if Correct.
Answer:
A
Step-by-step explanation:
We can see that Function A's y coordinate doubles every time. The function A = f(x) = 5(2)^x. It is an exponential growth function, and therefore y can never be 0. This means that A does not have an x-intercept.
Function B is a rational function. x cannot be 0, since that would result in an undefined number. This also means that B does not have an x-intercept.
11. A square with sides
3/8
inch has a total area of:
Answer:
[tex](\frac{3}{8}\,in )^2=\frac{9}{64} \,in^2=0.140625\,\,i^2[/tex]
Step-by-step explanation:
Recall that the formula for the area of a square of side L is: [tex]Area=L^2[/tex]
Therefore, for this case:
[tex]Area=L^2\\Area = (\frac{3}{8} \,in)^2\\Area=\frac{9}{64} \,\,in^2\\Area=0.140625\,\,in^2[/tex]
Which graph has a slope of 1/4?
Answer:Please include images of the graphs!
Step-by-step explanation:
Look at each graph given. Ensure that there is a line, and that you can locate two points on the line given.
Use the following equation to get the slope:
m (slope) = (y₂ - y₁)/(x₂ - x₁)
Note that you can obtain the numbers for the equation by getting two points on the number line. Plug in the numbers by variables:
(x₁ , y₁) & (x₂ , y₂)
In this equation, make sure that the slope (m) will equal 1/4 (given).
The full equation that you will use is:
1/4 = (y₂ - y₁)/(x₂ - x₁)
Find the graph that will satisfy this equation.
Maria has $39.00 that she can spend on school supplies. If she spends $18.00 on pens and pencils, how many packs of notebook paper can she buy if the notebook paper costs $3.00 a pack, including tax? Choose the graph that shows your answer.
Answer:
Please show the graph choice it sounds linear xy (positive)
or parallel depending on how much pens and pencils were.
We know $18 purchased more than 1 pack so this divided by notebook shws us at least 6 per notepack paper or so many packs of pen that cost $18 ffor pens were ratio to 1 pack of paper. ie) if pens were £2 pack then while we understand it could have been as many as 9 we divide by how many we find or bought by the amount of notepaper books to determine the rate and distribution of the money.
Step-by-step explanation:
$39 - $18 = $21 left over
21/3 = 7 packs of note paper can be purchased..
What is the inverse of f(x)-x/x+2, where x ≠ -2
Step-by-step explanation:
You can take the inverse of a function by replacing all x-values in the equation with y-values and vice versa and subsequently solving for y:
Equation given:
[tex]f(x) = \frac{-x}{x+2}[/tex]
Replace all x-values with y and all y-values with x:
[tex]x = \frac{-y}{y+2}[/tex]
Solve for y:
[tex]x(y+2) = -y\\\\xy + 2x = -y\\\\2x = -y - xy\\\\2x = y(-1+-x)\\\\-\frac{2x}{x+1} =y[/tex]
This is the inverse of f(x), where x ≠ 2..
a 680g patient comes in with diarrhea. the doctor orders anti-diarrhea medication at a dosage of 15 mcg/kg TID x 3 days. rhye medication concentration 50mcg/ml. What is the patients dose in MCG? What is the total volume of medication you will send home?
Answer:
dose in MCG = 10.2 mcg
Total volume to be sent home = 1.836 ml (1836μl)
Step-by-step explanation:
weight of patient = 680g
dosage in mcg of medication = 15mcg/kg
This means that
for every 1kg weight, 15mcg is given,
since 1kg = 1000g, we can also say that for every 1000g weigh, 15mcg is given.
1000g = 15mcg
1g = 15/1000 mcg = 0.015 mcg
∴ 680g = 0.015 × 680 = 10.2 mcg
Dosage in MCG = 10.2 mcg
Next, we are also told ever ml volume of the drug contains 50 mcg weight of the drug (50mcg/ml). This can also be written as:
50mcg = 1 ml
1 mcg = 1/50 ml = 0.02 ml
∴ 10.2 mcg = 10.2 × 0.02 = 0.204 ml
since the medication is to be taken TID (three times daily) for 3 days, the total number of times the drug is to be taken = 9 times.
therefore, the total volume required = 0.204 × 9 = 1.836 ml (1836 μl)
A linear function and its inverse are given.
y=4x-3
y=1/4x+3/4
Which tables could be used to verify that the functions are inverses of each other? Select two options.
x:1, 3, 5, 7, 9
y:1, 3, 5, 7, 9
x:-23, -15, -3, 1, 13
y:-5, -3, 0, 1, 4
x:-18, -12, 0, 3, 9
y:-24, -18, -6, -3, 3
x:-5, -3, 0, 1, 4
y:-23, -15, -3, 1, 13
x:-24, -18, -6, -3, 3
y:-18, -12, 0, 3, 9
Answer:
x: -5, -3, 0, 1, 4
y:-23, -15, -3, 1, 13 for the function.
x:-23, -15, -3, 1, 13
y: -5, -3, 0, 1, 4 for the inverse.
Step-by-step explanation:
we know that if we have the function f(x) = y, then the inverse of f(x) (let's call it g(x)) is such that:
g(y) = x.
now we have
y=4x-3
y=(1/4)x+3/4
The only table that works for our first function is:
x: -5, -3, 0, 1, 4
y:-23, -15, -3, 1, 13
You can see this by replacing the values of x and see if the value of y also coincides.
Then, using the fact that the other table must be for the inverse, we should se a table with the same values, but where the values of x and y are interchanged.
The second table is that one:
x:-23, -15, -3, 1, 13
y: -5, -3, 0, 1, 4
Answer: B and D
x:-23, -15, -3, 1, 13
y:-5, -3, 0, 1, 4
x:-5, -3, 0, 1, 4
y:-23, -15, -3, 1, 13
Step-by-step explanation:
6th grade math :) ........
Answer:
Step-by-step explanation:
1) d
2) c
1) 3 hearts, 7 other shapes that isn't hearts
2) 2 triangs, 5 circles
Answer:
1) d
2) c
Step-by-step explanation:
looks like i was wrong last time lol, this is right for sure tho, i see what i did wrong, sorry
What is the value of X ? A-17 B-26 C-39 D-41
Answer:
D.
Step-by-step explanation:
It's a right triangle so
[tex]x^2=40^2+9^2[/tex]
x = 41
Given that it was less then 80degrees on a given day, what is the probability that it also rained that day?
The probability that it also rained that day would be 0.30
A store has 8 puppies, including 3 poodles, 3 terries, and 2 retrievers. If Rebecca and Jas, in that order, each select one puppy at random without replacement, find the probability that Jas Selects a retriever, given that Rebecca selects a poodle.
Answer:
2/7
Step-by-step explanation:
Since Rebecca is garunteed to pick a poodle, there are 7 puppies left. There are 2 retrievers so the probability is 2/7
Answer:2/7
Step-by-step explanation:
Solve the following inequality. |-2x + 1| < 13
Please help!!!!
Answer:
x>−6 and x<7
Step-by-step explanation:
Let's solve your inequality step-by-step.
|−2x+1|<13
Solve Absolute Value.
|−2x+1|<13
We know−2x+1<13and−2x+1>−13
−2x+1<13(Condition 1)
−2x+1−1<13−1(Subtract 1 from both sides)
−2x<12
−2x
−2
<
12
−2
(Divide both sides by -2)
x>−6
−2x+1>−13(Condition 2)
−2x+1−1>−13−1(Subtract 1 from both sides)
−2x>−14
−2x
−2
>
−14
−2
(Divide both sides by -2)
x<7
Answer:
x>−6 and x<7
Use the drop-down menus to complete each equation so the statement about its solution is true.
No Solutions
No Solutions
2x+5+2x+3x= _ x +_
One Solution
2x+5+2x+3x=_ x + _
Infinitely Many Solutions
2x+5+2x+3x= _x +_
Answer:
7x+16x+17x+5Step-by-step explanation:
No Solutions
There will be no solutions when the left side is inconsistent with the right side:
2x +5 +2x +3x = 7x +1
7x +5 = 7x +1 . . . . . . no value of x will make this true
__
One Solution
There will be one solution when the left side and right side are not inconsistent and not the same.
2x +5 +2x +3x = 6x +1
7x +5 = 6x +1
x = -4 . . . . . . . . add -6x-5 to both sides
__
Infinitely Many Solutions
There will be an infinite number of solutions when the equation is true for any value of x. This will be the case when the left side and right side are identical.
2x +5 +2x +3x = 7x +5
7x +5 = 7x +5 . . . . . true for all values of x
_____
Comment on these solutions
You have not provided the contents of any of the drop-down menus, so we cannot say for certain what the answers should be--except in the case of "infinitely many solutions." For "no solutions", the coefficient of x must be 7 and the constant must not be 5. For "one solution" the coefficient of x cannot be 7, and the constant can be anything.
Answer:
No Solutions: 7x+1
One Solution: 6x+1
Infinitely Many Solutions: 7x+5
CAN SOMEONE HELP ME IN THIS INTEGRAL QUESTION PLS
''Find the surface area between the z = 1 and z = 4 planes of z = x ^ 2 + y ^ 2 paraboloid.''
Due to the symmetry of the paraboloid about the z-axis, you can treat this is a surface of revolution. Consider the curve [tex]y=x^2[/tex], with [tex]1\le x\le2[/tex], and revolve it about the y-axis. The area of the resulting surface is then
[tex]\displaystyle2\pi\int_1^2x\sqrt{1+(y')^2}\,\mathrm dx=2\pi\int_1^2x\sqrt{1+4x^2}\,\mathrm dx=\frac{(17^{3/2}-5^{3/2})\pi}6[/tex]
But perhaps you'd like the surface integral treatment. Parameterize the surface by
[tex]\vec s(u,v)=u\cos v\,\vec\imath+u\sin v\,\vec\jmath+u^2\,\vec k[/tex]
with [tex]1\le u\le2[/tex] and [tex]0\le v\le2\pi[/tex], where the third component follows from
[tex]z=x^2+y^2=(u\cos v)^2+(u\sin v)^2=u^2[/tex]
Take the normal vector to the surface to be
[tex]\dfrac{\partial\vec s}{\partial u}\times\dfrac{\partial\vec s}{\partial u}=-2u^2\cos v\,\vec\imath-2u^2\sin v\,\vec\jmath+u\,\vec k[/tex]
The precise order of the partial derivatives doesn't matter, because we're ultimately interested in the magnitude of the cross product:
[tex]\left\|\dfrac{\partial\vec s}{\partial u}\times\dfrac{\partial\vec s}{\partial v}\right\|=u\sqrt{1+4u^2}[/tex]
Then the area of the surface is
[tex]\displaystyle\int_0^{2\pi}\int_1^2\left\|\dfrac{\partial\vec s}{\partial u}\times\dfrac{\partial\vec s}{\partial v}\right\|\,\mathrm du\,\mathrm dv=\int_0^{2\pi}\int_1^2u\sqrt{1+4u^2}\,\mathrm du\,\mathrm dv[/tex]
which reduces to the integral used in the surface-of-revolution setup.
Determine the discriminant for the quadratic equation -3=x2+4x+1. Based on the discriminant value, how many real number
solutions does the equation have?
Discriminant = b2-4ac
0
1
2
o 12
Save and Exit
Next
Submit
Mark this and return
le
Step-by-step explanation:
work is shown and pictured
The discriminant of quadratic equation is,
⇒ D = 0
What is Quadratic equation?
The definition of a quadratic as a second-degree polynomial equation demands that at least one squared term must be included. It also goes by the name quadratic equations. The quadratic equation has the following generic form: ax² + bx + c = 0
We have to given that;
Quadratic equation is,
⇒ - 3 = x² + 4x + 1
Now, We can write as;
⇒ x² + 4x + 1 + 3 = 0
⇒ x² + 4x + 4 = 0
Hence, Discriminant of quadratic equation is,
⇒ D = b² - 4ac
⇒ D = (4)² - 4×1×4
⇒ D = 16 - 16
⇒ D = 0
Thus, The discriminant of quadratic equation is,
⇒ D = 0
Learn more about the quadratic equation visit:
brainly.com/question/1214333
#SPJ7
Can You please help me cause I'm gangsta Simplify (5^-2)^4
Answer:
( 5 ^ -2)^4
= 5 ^ -8
= 1 /5^8
= 1 / 390,625
Which expression would be easier to simplify if you used the associative
property to change the grouping?
A. 0.85+ (0.15 +(-3)
B. [(-3)+(-3)] +(-3)
C. (160 + 40 + 27
O D. 1+*+(-))
SUBMIT
P
Answer:
A . 0.85 + (0.15 +(-3)) = -2
B . [(-3)+(-3)]+(-3) = - 9
Step-by-step explanation:
Explanation:-
Associative property with addition
(a+(b+c)) = (a+b) + c
A)
Given 0.85 + (0.15 +(-3)) = (0.85 +0.15)+(-3)
= 1 - 3
= -2
B) Given [(-3)+(-3)]+(-3) = ( (-3)+[( -3)+(-3))]
= ( -3 +[-3-3]
= -3 -6
= -9
Final answer:-
A . 0.85 + (0.15 +(-3)) = -2
B . [(-3)+(-3)]+(-3) = - 9
One number is 4 plus one half of another number. Their sum is 31. Find the numbers.
Answer:
18, 13
Step-by-step explanation:
x=4+1/2y
x+y=31
4+1/y+y=31
3/2y=27
y=18
x=31-18=13
Answer:
13 & 18
Step-by-step explanation:
Create the formulas:
0.5x+4=y
x+y=31
0.5x+4=y
Multiply both sides by 2
x+8=2y
x+y=31
Subtract 31 from both sides
x+y-31=0
Subtract y from both sides
x-31= -y
Multiply both sides by -1
-x+31=y
Multiply both sides by 2
-2x+62=2y
Combine equations:
-2x+62=x+8
Add 2x to both sides
62=3x+8
Subtract 8 from both sides
3x=54
Divide both sides by 3
x=18
0.5x+4=y
Subtract y from both sides
0.5x-y+4=0
Subtract 0.5x from both sides
-y+4= -0.5x
Multiply both sides by -1
y-4=0.5x
Multiply both sides by 2
2y-8=x
x+y=31
Subtract y from both sides
x= -y+31
Combine equations:
2y-8= -y+31
Add y to both sides
3y-8=31
Add 8 to both sides
3y=39
Divide both sides by 3
y=13
help me please!!!! Dan's car depreciates at a rate of 8% per year. By what percentage has Dan's car depreciated after 3 years? Give your answer to the nearest percent.
Answer:
22%
Step-by-step explanation:
Car's price is reduced by 8% or 0.92 times a year
after 3 years it will make:
0.92³= 0.778688≈ 0.78 timesor
0.78 = 1- 0.22price decrease = 22%Answer:
Hello!
Here is your answer:
22%
I hope I was able to help you. If not, please let me know!
Step-by-step explanation:
If the reciprocal of a number is multiplied by 1 less than the original number, the results exceed 1/2 the reciprocal of the original number by 5/8. Find the number.
Answer:
4
Step-by-step explanation:
Let's try this a different way than perhaps the usual way. Let r represent the reciprocal of the number.
r(1/r -1) -1/2r = 5/8
1 -r -1/2r = 5/8 . . . . . . eliminate parentheses
-3/2r = -3/8 . . . . . . . . collect terms, subtract 1
(-3/2)/(-3/8) = 1/r = 4 . . . . . divide by (-3/8)r because we actually want 1/r
The number is 4.
_____
Check
The reciprocal of the number is 1/4.
1 less than the original number is 4 -1 = 3. The product of these is 3/4.
__
Half the reciprocal of the original number is (1/2)(1/4) = 1/8.
Then the difference between these is ...
3/4 -1/8 = (6 -1)/8 = 5/8 . . . . as required.
A mountain bike is priced at $413. If the sales tax is 6.5 percent, what is the cost to purchase the mountain bike? Round to the
nearest cent if necessary.
$26.85
$28.91
$437.78
$439.85
answer: D) 439.85
Step-by-step explanation:
we are given the price of the bike which is $413.
we are also given the sales tax which is 6.5%.
sales tax is added to the original price to give us our total. so in order to find the total cost we need to find what the 6.5% sales tax is and add it to our original price. to find the sales tax number in dollars we need to set up our formula. The easiest formula is to use a proportion. X is out of 413 = 6.5% is out of 100%. X/413=6.5/100. We can then cross multiply then divide. 6.5 times 413=2,684.5. then divide 2684.5÷100= 26.845.
we need to round up to the nearest cent since we are working with dollars and cents 26.85. 26.85 is 6.5% of the price of the bike which is 413. Now we just simply add the tax to the original price and we get the cost. 413+26.85=439.85
Answer: The answer is D) 439.85
Step-by-step explanation:
find the equivalent expression using the same bases. (21 x15)9
Answer:
2835
Step-by-step explanation:
(21×15)9=
(315)9=
2835
A nutritionist wants to determine how much time nationally people spend eating and drinking. Suppose for a random sample of 1082 people age 15 or older, the mean amount of time spent eating or drinking per day is 1.53 hours with a standard deviation of 0.71 hour.
a. Determine and interpret a 95% confidence interval for the mean amount of time Americans age 15 or older spend eating and drinking each day
b. The nutritionist is 95% confident that the amount of time spent eating or drinking per day for any individual is between_________and_________hours.
c. There is a 95% probability that the mean amount of time spent eating or drinking per day is between and hours.
d. The nutritionist is 95% confident that the mean amount of time spent eating or drinking per day is between_______and_____________
Answer:
a) The 95% confidence interval for the mean amount of time Americans age 15 or older spend eating and drinking each day is (1.49, 1.57).
d) The nutritionist is 95% confident that the mean amount of time spent eating or drinking per day for any individual is between 1.49 and 1.57 hours.
(c and b can not be concluded from the confidence interval)
Step-by-step explanation:
We have to calculate a 95% confidence interval for the mean.
The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.
The sample mean is M=1.53.
The sample size is N=1082.
When σ is not known, s divided by the square root of N is used as an estimate of σM:
[tex]s_M=\dfrac{s}{\sqrt{N}}=\dfrac{0.71}{\sqrt{1082}}=\dfrac{0.71}{32.89}=0.022[/tex]
The degrees of freedom for this sample size are:
[tex]df=n-1=1082-1=1081[/tex]
The t-value for a 95% confidence interval and 1081 degrees of freedom is t=1.962.
The margin of error (MOE) can be calculated as:
[tex]MOE=t\cdot s_M=1.962 \cdot 0.022=0.042[/tex]
Then, the lower and upper bounds of the confidence interval are:
[tex]LL=M-t \cdot s_M = 1.53-0.042=1.49\\\\UL=M+t \cdot s_M = 1.53+0.042=1.57[/tex][tex]LL=M-t \cdot s_M = 1.53-0.042=1.49\\\\UL=M+t \cdot s_M = 1.53+0.042=1.57[/tex]
The 95% confidence interval for the mean is (1.49, 1.57).
2009-2202+1234-2 equals
Step-by-step explanation:
1039
This is the correct answer
An article suggests the uniform distribution on the interval (6.5, 19) as a model for depth (cm) of the bioturbation layer in sediment in a certain region.(a) What are the mean and variance of depth
Answer:
The mean of depth is 12.75cm.
The variance of depth is of 13.02 cm².
Step-by-step explanation:
An uniform probability is a case of probability in which each outcome is equally as likely.
For this situation, we have a lower limit of the distribution that we call a and an upper limit that we call b.
The mean of the uniform distribution is:
[tex]M = \frac{a+b}{2}[/tex]
The variance of the uniform distribution is given by:
[tex]V = \frac{(b-a)^{2}}{12}[/tex]
Uniform distribution on the interval (6.5, 19)
This means that: [tex]a = 6.5, b = 19[/tex]
So
Mean:
[tex]M = \frac{6.5+19}{2} = 12.75[/tex]
The mean of depth is 12.75cm.
Variance:
[tex]V = \frac{(19 - 6.5)^{2}}{12} = 13.02[/tex]
The variance of depth is of 13.02 cm².
The amount of time, in minutes, that a woman must wait for a cab is uniformly distributed between zero and 12 minutes, inclusive. What is the probability that a person waits fewer than 11 minutes
Answer:
[tex] P(X\leq x) =\frac{x-a}{b-a}, a \leq x \leq b[/tex]
And using this formula we have this:
[tex] P(X<11) = \frac{11-0}{12-0}= 0.917[/tex]
Then we can conclude that the probability that that a person waits fewer than 11 minutes is approximately 0.917
Step-by-step explanation:
Let X the random variable of interest that a woman must wait for a cab"the amount of time in minutes " and we know that the distribution for this random variable is given by:
[tex] X \sim Unif (a=0, b =12)[/tex]
And we want to find the following probability:
[tex] P(X<11)[/tex]
And for this case we can use the cumulative distribution function given by:
[tex] P(X\leq x) =\frac{x-a}{b-a}, a \leq x \leq b[/tex]
And using this formula we have this:
[tex] P(X<11) = \frac{11-0}{12-0}= 0.917[/tex]
Then we can conclude that the probability that that a person waits fewer than 11 minutes is approximately 0.917
Suppose cattle in a large herd have a mean weight of 3181lbs and a standard deviation of 119lbs. What is the probability that the mean weight of the sample of cows would differ from the population mean by greater than 11lbs if 49 cows are sampled at random from the herd
Answer:
51.56% probability that the mean weight of the sample of cows would differ from the population mean by greater than 11lbs if 49 cows are sampled at random from the herd
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal probability distribution
When the distribution is normal, we use the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
In this question, we have that:
[tex]\mu = 3181, \sigma = 119, n = 49, s = \frac{119}{\sqrt{49}} = 17[/tex]
What is the probability that the mean weight of the sample of cows would differ from the population mean by greater than 11lbs if 49 cows are sampled at random from the herd
Lower than 3181 - 11 = 3170 lbs or greater than 3181 + 11 = 3192 lbs. Since the normal distribution is symmetric, these probabilities are equal. So i will find one of them, and multiply by 2.
Probability of mean weight lower than 3170 lbs:
This is 1 subtracted by the pvalue of Z when X = 3170. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{3170 - 3181}{17}[/tex]
[tex]Z = -0.65[/tex]
[tex]Z = -0.65[/tex] has a pvalue of 0.2578
2*0.2578 = 0.5156
51.56% probability that the mean weight of the sample of cows would differ from the population mean by greater than 11lbs if 49 cows are sampled at random from the herd
Dan was thinking of a number. Dan adds 10 to it, then doubles it and gets an answer of 56.6. What was the original numbe
Answer:
[tex]\fbox{\begin{minipage}{5em}A = 18.3\end{minipage}}[/tex]
Step-by-step explanation:
Given:
Dan was thinking of a number.
Dan adds 10 to it, then doubles it and gets an answer of 56.6.
Solve for:
Dan's original number
Step 1: Clarify the problem:
Denote Dan's original number as A
Dan adds 10 to A => 10 + A, then
Dan doubles this sum => 2 x (10 + A), then
Dan gets an answer of 56.6 => 2 x (10 + A) = 56.6
Step 2: Solve for the defined equation:
2 x (10 + A) = 56.6
Let's divide both sides of equation by 2:
2 x (10 + A)/2 = 56.6/2
We simplify both sides after division:
10 + A = 28.3
Let's transfer all numbers to the right side, except A (the sign of 10 is changed from + to -)
A = 28.3 - 10
Let's perform the subtraction to get A:
A = 18.3
Hope this helps!
:)
Engineers must consider the breadths of male heads when designing helmets. The company researchers have determined that the population of potential clientele have head breadths that are Normally distributed with a mean of 6.5 inches and a standard deviation of 1.2 inches. According to the 68-95-99.7 rule, we expect 95% of head breadths to be:___________.
Answer:
"According to the 68-95-99.7 rule, we expect 95% [95.45%] of head breadths to be" between 4.1 inches and 8.9 inches.
Step-by-step explanation:
According to the 68-95-99.7 rule, approximately:
68% (more precisely, 68.27%) of the data from the normal distribution lie one standard deviation, [tex] \\ \sigma[/tex], above and below the population mean, [tex] \\ \mu[/tex].95% (more precisely, 95.45%) of the data lie two standard deviations, [tex] \\ 2\sigma[/tex], above and below the population mean, [tex] \\ \mu[/tex], and finally,99.7 (or more precisely, 99.73%) of the data lie three standard deviations, [tex] \\ 3\sigma[/tex], above and below the population mean, [tex] \\ \mu[/tex].Then, if we have--from the question--that:
The random variable is head breadths.This variable follows a normal distribution.The population's mean for this distribution is [tex] \\ \mu = 6.5[/tex] inches.The population's standard deviation is [tex] \\ \sigma =1.2[/tex] inches.We have to remember that two parameters characterize a normal distribution: the population's mean and the population's standard deviation. So, mathematically, the distribution we have from question is [tex] \\ N(6.5, 1.2)[/tex].
For 95% (95.45%) of the head breadths, we expect that they are two standard deviations below and above the population's mean.
For solving this, we need to use the cumulative standard normal distribution (in case we need to find probabilities) and also use standardized values or z-scores:
[tex] \\ z = \frac{x - \mu}{\sigma}[/tex] [1]
A z-score "tells us" the distance from the mean in standard deviations units. If the z-score is positive, it is above the mean. If it is negative, it is below the mean.
Since 95% (95.45%) of the head breadths are two standard deviations (above and below the mean), we have (using [1]):
[tex] \\ \pm2 = \frac{x - \mu}{\sigma}[/tex]
But we already know that [tex] \\ \mu=6.5[/tex] inches and [tex] \\ \sigma=1.2[/tex] inches.
Thus (without using units) for values above the population's mean:
[tex] \\ 2 = \frac{x - 6.5}{1.2}[/tex]
Solving the equation for x, we multiply by 1.2 at each side of [1] :
[tex] \\ 2 * 1.2 = \frac{x - 6.5}{1.2} * 1.2[/tex]
[tex] \\ 2 * 1.2 = (x - 6.5)\frac{1.2}{1.2}[/tex]
[tex] \\ 2 * 1.2 = (x - 6.5)\frac{1.2}{1.2}[/tex]
[tex] \\ 2 * 1.2 = (x - 6.5)*1[/tex]
[tex] \\ 2 * 1.2 = x - 6.5[/tex]
Adding 6.5 at each side of the previous equation:
[tex] \\ (2 * 1.2) + 6.5 = x - 6.5 + 6.5[/tex]
[tex] \\ (2 * 1.2) + 6.5 = x + 0[/tex]
[tex] \\ (2 * 1.2) + 6.5 = x[/tex]
Therefore, the raw value, x, in the distribution that is two standard deviations above the population's mean is:
[tex] \\ x = (2 * 1.2) + 6.5[/tex]
[tex] \\ x = 2.4 + 6.5[/tex]
[tex] \\ x = 8.9[/tex] inches.
For two standard deviations below the mean, we proceed in the same way:
[tex] \\ -2 = \frac{x - 6.5}{1.2}[/tex]
[tex] \\ -2*1.2 = x - 6.5[/tex]
[tex] \\ (-2*1.2) + 6.5 = x[/tex]
[tex] \\ x = (-2*1.2) + 6.5[/tex]
[tex] \\ x = -2.4 + 6.5[/tex]
[tex] \\ x = 4.1[/tex] inches
Therefore, "according to the 68-95-99.7 rule, we expect 95% [95.45%] of head breadths to be" between 4.1 inches and 8.9 inches.
The graph below shows these values, and the shaded area represents 95% of the data, or, to be more precise, 95.45% (0.954499).
What is 2 1/2 + 1 1/3
Answer:
[tex]=3\frac{5}{6}[/tex]
Step-by-step explanation:
[tex]2\frac{1}{2}+1\frac{1}{3}\\\mathrm{Add\:whole\:numbers}\:2+1:\quad 3\\\mathrm{Combine\:fractions}\:\frac{1}{2}+\frac{1}{3}:\quad \frac{5}{6}\\=3\frac{5}{6}[/tex]