A college student is interested in investigating the TV-watching habits of her classmates and surveys 20 people on the number of hours they watch per week. The results are provided below. Calculate the 80% confidence interval of the true average number of hours of TV watched per week.
P.S: excel formola needed only. For lower and Upper Bound
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Answer:
80% confidence interval of the true average number of hours of TV watched per week is [8.28 hours, 11.02 hours].
Step-by-step explanation:
We are given that a college student is interested in investigating the TV-watching habits of her classmates and surveys 20 people on the number of hours they watch per week. The results are provided below;
Hours of TV per week (X): 6, 14, 13, 6, 16, 10, 19, 4, 5, 5, 18, 8, 7, 14, 8, 8, 9, 12, 6, 5.
Firstly, the Pivotal quantity for 80% confidence interval for the true average is given by;
P.Q. = [tex]\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }[/tex] ~ [tex]t_n_-_1[/tex]
where, [tex]\bar X[/tex] = sample mean number of hours of TV watched per week = [tex]\frac{\sum X}{n}[/tex] = 9.65
s = sample standard deviation = [tex]\sqrt{\frac{\sum (X -\bar X)^{2} }{n-1} }[/tex] = 4.61
n = sample of people = 20
[tex]\mu[/tex] = true average number of hours of TV watched per week
Here for constructing 80% confidence interval we have used One-sample t-test statistics as we don't know about population standard deviation.
So, 80% confidence interval for the true average, [tex]\mu[/tex] is ;
P(-1.33 < [tex]t_1_9[/tex] < 1.33) = 0.80 {As the critical value of t at 19 degrees of
freedom are -1.33 & 1.33 with P = 10%}
P(-1.33 < [tex]\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }[/tex] < 1.33) = 0.80
P( [tex]-1.33 \times {\frac{s}{\sqrt{n} } }[/tex] < [tex]{\bar X-\mu}[/tex] < [tex]1.33 \times {\frac{s}{\sqrt{n} } }[/tex] ) = 0.80
P( [tex]\bar X-1.33 \times {\frac{s}{\sqrt{n} } }[/tex] < [tex]\mu[/tex] < [tex]\bar X+1.33 \times {\frac{s}{\sqrt{n} } }[/tex] ) = 0.80
80% confidence interval for [tex]\mu[/tex] = [ [tex]\bar X-1.33 \times {\frac{s}{\sqrt{n} } }[/tex] , [tex]\bar X+1.33 \times {\frac{s}{\sqrt{n} } }[/tex] ]
= [ [tex]9.65-1.33 \times {\frac{4.61}{\sqrt{20} } }[/tex] , [tex]9.65+1.33 \times {\frac{4.61}{\sqrt{20} } }[/tex] ]
= [8.28 hours, 11.02 hours]
Therefore, 80% confidence interval of the true average number of hours of TV watched per week is [8.28 hours, 11.02 hours].
Determine the area of the shaded region
Answer:
61.76 ft^2
Step-by-step explanation:
First find the area of the rectangle without the circle
A = l*w = 14*8 =112
Then find the area of the circle
The diameter is 8 so the radius is 8/2 =4
A = pi r^2 = 3.14 * 16 =50.24
The shaded region is the rectangle minus the circle
112-50.24 =61.76 ft^2
a mathematical statement regarded as undecided or cannot be proved to be true or false is called what
Answer: axiom
Step-by-step explanation:
If a random sample of size 774 is selected, what is the probability that the proportion of persons with a retirement account will differ from the population proportion by less than 3%
Suppose 43% of the population has a retirement account. If a random sample of size 774 is selected, what is the probability that the proportion of persons with a retirement account will differ from the population proportion by less than 3%?
Answer:
the probability that the proportion of persons with a retirement account will differ from the population proportion by less than 3% is 0.9082
Step-by-step explanation:
Given that:
sample size n = 774
Let P be the population proportion for having a retirement account = 0.43
Also
Let consider [tex]\hat p[/tex] be the sample proportion of having a retirement account.
However; as n is > 30 ; we can say:
[tex]\mathbf{\mu_{\hat p} = 0.43}[/tex] ;
[tex]\mathbf{\sigma_{\hat p^2} = \dfrac{p(1-p)}{n}}[/tex]
⇒ [tex]\mathbf{\sigma_{\hat p^2} = \dfrac{0.43(1-0.43)}{774}}[/tex]
⇒ [tex]\mathbf{\sigma_{\hat p^2} = \dfrac{0.43(0.57)}{774}}[/tex]
So; we need P( the sample proportion will differ from 'p' by less than 3% i.e 0.03)
[tex]=P(| \hat p- p|< 0.03)[/tex]
[tex]=P(| \hat p- \mu _p|< 0.03)[/tex]
[tex]= P ( |\dfrac{\hat P - \mu_p}{\sigma_{\hat p}}|< \dfrac{0.03}{\sqrt{ \dfrac{0.43*0.57}{774} }})[/tex]
[tex]= P(|Z|<1.6859)\ \ \ \ [Z=(\dfrac{\hat P - \mu_{\hat P}}{\sigma_{\hat P}}) \sim N(0,1)][/tex]
[tex]= P(-1.6859 <Z<1.6859) \\ \\ = \Phi(1.6859)- \Phi (-1.6859) \\ \\ = \Phi (1.6859) - (1- \Phi(1.6859) \\ \\ = 2 \Phi (1.6859)-1[/tex]
From Normal Cumulative Distribution Function Table
[tex]= 2*0.9541 -1[/tex]
= 1.9082 - 1
= 0.9082
Thus; the probability that the proportion of persons with a retirement account will differ from the population proportion by less than 3% is 0.9082
Which pair of complex numbers has a real-number product?
Answer:
Step-by-step explanation:
the complex number and its conjugate
Answer:
(1+3i)(1-3i)
Step-by-step explanation:
Divide £2.28 btw eve and amelie in the ratio 9:5 give your answer to the nearest penny Eve gets ? And amelie gets ?
Answer:
Eve gets 1.47 and Amelie gets 0.81
Step-by-step explanation:
the ratio is 9 to 5 so we can say 9x + 5x=2.28
14x=2.28
x=0.16
so eve gets 9x = 9(2.28/14) = 1.47
and amelie gets 5x = 5(2.28/14) = 0.81
Fredrick slept 4 hours each day in weekdays and 8 hours in weekend. How many
hours did he sleep in 5 weeks?
Answer:
180 or 1260
Step-by-step explanation:
4*5=20
8*2=16
20+16=36
36*5=180
180*7=1260
sorry it took so long im only in 8th grade but im doing 11th grade classes because im smart i guess
* If you are given the measurements of two sides of a triangle,
what will be true about the triangles you make?
Answer:both sides will be equal
Step-by-step explanation:
The table represents a function. A 2-column table with 5 rows. The first column is labeled x with entries negative 6, 7, 4, 3, negative 5. The second column is labeled f of x with entries 8, 3, negative 5, negative 2, 12. Which value is an output of the function? –6 –2 4 7The table represents a function. A 2-column table with 5 rows. The first column is labeled x with entries negative 6, 7, 4, 3, negative 5. The second column is labeled f of x with entries 8, 3, negative 5, negative 2, 12. Which value is an output of the function? –6 –2 4 7
Answer:
-2 is an output of the function.
Step-by-step explanation:
The given table is as follows:
[tex]\left[\begin{array}{cc}{x}&f(x)\\-6&8\\7&3\\4&-5\\3&-2\\-5&12\end{array}\right][/tex]
Here, the values written on the left side of table i.e. values of [tex]x[/tex] are known as the domain values or input values to a function.
The values written on the right side of table i.e. values of [tex]f(x)[/tex] are known as the range values or output values of the function [tex]f(x)[/tex].
Let us consider the pairs of values:
(-6,8) then left side value is of [tex]x[/tex] and right side value is of [tex]f(x)[/tex]
i.e. when [tex]x=-6[/tex], the output value [tex]f(x) =8[/tex].
The same thing applies for all the pairs of values.
similarly for the pair (3,-2):
Left side value is of [tex]x[/tex] and right side value is of [tex]f(x)[/tex]
i.e. when [tex]x=3[/tex], the output value [tex]f(x) =-2[/tex].
So, the answer is:
-2 is an output of the function.
Answer:
-2
Step-by-step explanation:
What is the probability of selecting the 4 of spade or black diamond from a deck of 52 playing cards?
a) 2/52
b) 4/52
c) 3/52
d) 1/5
Answer:
b
Step-by-step explanation:
Answer:
he
Step-by-step explanation:
hi
x/3+1=7/15 what is the answer of my question
Answer:
efdm3rndne
Step-by-step explanation:
nenejej4ree2wiwiwwi3ieiej
Answer:
-8/5
Step-by-step explanation:
x/3+1= 7/15
x/3= 7/15-1
x/3= -8/15
x= - 8/5
The probability that a freshman at a certain college takes an introductory statistics class is 0.21. What is the probability that a randomly selected freshman from this college does not take an introductory statistics class
Answer:
[tex] P(A) = 0.21[/tex]
We want to find the probability that a randomly selected freshman from this college does not take an introductory statistics class, so then we can use the complement rule given by:
[tex] P(A') = 1-P(A)[/tex]
Where A is the event of interest (a freshman at a certain college takes an introductory statistics class) and A' the complement (a freshman at a certain college NOT takes an introductory statistics class) and then replacing we got:
[tex] P(A')=1-0.21= 0.79[/tex]
Step-by-step explanation:
For this problem we know that the probability that a freshman at a certain college takes an introductory statistics class is 0.21, let's define of interest as A and we can set the probability like this:
[tex] P(A) = 0.21[/tex]
We want to find the probability that a randomly selected freshman from this college does not take an introductory statistics class, so then we can use the complement rule given by:
[tex] P(A') = 1-P(A)[/tex]
Where A is the event of interest (a freshman at a certain college takes an introductory statistics class) and A' the complement (a freshman at a certain college NOT takes an introductory statistics class) and then replacing we got:
[tex] P(A')=1-0.21= 0.79[/tex]
A random sample of math majors taking an introductory statistics course were surveyed after completing the final exam. They were asked, "How many times did you review your final exam before handing it in to the professor?" The results are displayed in a probability density function for the random variable X, the number of times students reviewed their exam before handing it in. Find the standard deviation of X. Round the final answer to two decimal places. x P(X = x) 1 1/5 2 2/5 7 2/5
Answer:
[tex] E(X) =1 *\frac{1}{5} +2 *\frac{2}{5} +7*\frac{2}{5}= 3.8[/tex]
Now we can find the second moment with this formula:
[tex] E(X^2) = \sum_{i=1}^n X^2_i P(X_i)[/tex]
And replacing we got:
[tex] E(X^2) =1^2 *\frac{1}{5} +2^2 *\frac{2}{5} +7^2*\frac{2}{5}= 21.4[/tex]
The variance would be given by:
[tex] Var(X) =E(X^2) -[E(X)]^2 = 21.4 -[3.8]^2 = 6.96[/tex]
And the deviation would be:
[tex] Sd(X) =\sqrt{6.96}= 2.638[/tex]
Step-by-step explanation:
For this case we have the following distribution given:
X 1 2 7
P(X) 1/5 2/5 2/5
We need to begin finding the mean with this formula:
[tex] E(X) = \sum_{i=1}^n X_i P(X_i)[/tex]
And replacing we got:
[tex] E(X) =1 *\frac{1}{5} +2 *\frac{2}{5} +7*\frac{2}{5}= 3.8[/tex]
Now we can find the second moment with this formula:
[tex] E(X^2) = \sum_{i=1}^n X^2_i P(X_i)[/tex]
And replacing we got:
[tex] E(X^2) =1^2 *\frac{1}{5} +2^2 *\frac{2}{5} +7^2*\frac{2}{5}= 21.4[/tex]
The variance would be given by:
[tex] Var(X) =E(X^2) -[E(X)]^2 = 21.4 -[3.8]^2 = 6.96[/tex]
And the deviation would be:
[tex] Sd(X) =\sqrt{6.96}= 2.638[/tex]
we choose a sample of size 100 from a population of monthly cable bills having standard deviation $20 If we assume the population mean bill is $65, what is the probability mean of our sample is greater than $70.
Answer:
0.0062
Step-by-step explanation:
Find the standard error.
σ = 20 / √100
σ = 2
Find the z-score.
z = (x − μ) / σ
z = (70 − 65) / 2
z = 2.5
Find the probability.
P(Z > 2.5) = 1 − 0.9938
P(Z > 2.5) = 0.0062
Express the following in simplest a + bi form.
V9+1-36
O
-91
O
3 - 61
3 + 6
91
Answer:
3+6i
Step-by-step explanation:
I did it
Answer:3+6i
Step-by-step explanation:
Find the value of the logarithm.
log 110
Round your answer to the nearest thousandth.
Answer:
Log 110 = 2.041
Step-by-step explanation:
Log 110 can be simplified and reduced to
Log 110 = log (10*11)
Log 110 = log10 + log11
But log10 = 1
Log 11= unknown = x
10^x= 11
X= 1.0413926
Log 110 = 1+1.0413926
Log110 = 2.0413926
Log 110 = 2.041
Anyone know this at all?
Answer:
24.2
Step-by-step explanation:
You are given the hypotenuse and angle, and you want to find the length of the adjacent side.
The mnemonic SOH CAH TOA reminds you that the relation between angle and sides is ...
Cos = Adjacent/Hypotenuse
cos(41°) = x/32
x = 32·cos(41°)
x ≈ 24.2
he dot plot shows how many swimmers are in each line at a waterpark: Is the median or the mean a better measure of center for these data and why? Median, because the data are skewed and there is an outlier Median, because the data are symmetric and there are no outliers Mean, because the data are skewed and there is an outlier Mean, because the data are symmetric and there are no outliers
Answer:
Step-by-step explanation:
There's no plot, but I can give you this: Median is better with a large outlier, while mean is better for symmetry. Therefore, the correct answer would be either the first or fourth. Ofc, we can't see the plot so that's all I can give you.
Hope that helped,
-sirswagger21
What’s the correct answer for this question?
Answer:
C.
Step-by-step explanation:
1/2r = 2π/Cb
NEED ASAP!!!!
Which equation represents the grafted function
Answer:
sorry i meant c
Step-by-step explanation:
The number of traffic accidents at a certain intersection is thought to be well modeled by a Poisson process. If the probability of no accident within a year is 5 percent. What is the mean waiting time between accidents
if percent of 1 year was 5%:
meaning time between accidents must be atleast 1 week
The mean waiting time that exists between the accidents would be:
- 1 week
'Mean waiting time' is determined through the contemplated value of an odd(random/casual) variable.
Given that,
Probability(P) of no accident taking place in 1 year = 5%
Assuming T be the accidents' number that takes place during a year,
Since 5% is the probability or chance of no accident to take place,
The mean waiting time between accidents = 1 week at least via Poisson process.
Thus, 1 week would be the correct answer.
Learn more about 'Mean' here:
brainly.com/question/521501
The graph of Ax), shown below, resembles the graph of G(X) = x, but it has
been stretched and shifted. Which of the following could be the equation of
Fx)?
Answer:
sorry'but I don't know the answer
The cost to rent a moving truck is a flat fee of $25 plus $0.60 per mile. The equation c = 25 + 0.6m models the cost, c, in dollars for the number of miles, m, traveled in the truck. Identify the independent and dependent variables. The is the independent variable. The is the dependent variable.
Answer:
The m is the independent variableThe c is the dependent variableStep-by-step explanation:
In this scenario, cost depends on mileage. Thus cost is the dependent variable.
As a general rule, if you have the form ...
a = (some expression involving b)
you will find that "a" is the dependent variable, and "b" is the independent variable.
This problem statement gives you ...
c = (an expression involving m)
"c" is the dependent variable; "m" is the independent variable.
The independent variable is m and the dependent variable is c.
What are the dependent and independent variables?The dependent variable is the outcome or result that is affected by the independent variable. The independent variable is the factor that is changed or manipulated in order to observe the effect on the dependent variable.
Given that, the cost to rent a moving truck is a flat fee of $25 plus $0.60 per mile.
The equation c = 25 + 0.6m models the cost, c, in dollars for the number of miles, m, traveled in the truck.
In the given equation c = 25 + 0.6m, c is the dependent variable and the m is the independent variable.
Therefore, the independent variable is m and the dependent variable is c.
Learn more about the independent variable here:
brainly.com/question/29430246.
#SPJ7
Please help will mark brainliest.
Answer:
parallel lines both have slope 1/3; non-parallel lines both have length 5
Step-by-step explanation:
It generally works well to follow instructions.
A graph of the points shows you that the parallel sides are RA and PT. The difference between the end points of these segments are ...
A - R = (6, 8) -(-3, 5) = (9, 3) = (Δx, Δy)
So, the slope of RA is Δy/Δx = 3/9 = 1/3
And the other difference and slope are ...
P -T = (9, 4) -(-3, 0) = (12, 4) ⇒ Δy/Δx = 4/12 = 1/3
The slope of RA is the same as the slope of PT, so those segments are parallel.
__
The length of segment TR can be found from the differences of the end point coordinates:
R - T = (-3, 5) -(-3, 0) = (0, 5)
Since these points are on the same vertical line, this tells us the segment length is 5.
The other difference of coordinates is ...
A - P = (6, 8) -(9, 4) = (-3, 4)
The distance formula tells us the length of AP is then ...
AP = √((-3)² +4²) = √25 = 5
Non-parallel sides TR and AP have the same lengths, so the trapezoid is isosceles.
Determine whether the study depicts an observational study or an experiment.
A study is conducted to determine if there is a relationship between stomach cancer and alcohol consumption.alcohol consumption. Everyone treated at a hospital for stomach cancer was asked Everyone treated at a hospital for stomach cancer was asked about their alcohol consumption.
a. The study is an experiment because the researchers control one variable to determine the effect on the response variable.
b. The study is an observational study because the researchers control one variable to determine the effect on the response variable.
c. The study is an observational study because the study examines individuals in a sample, but does not try to influence the response variable.
d. The study is an experiment because the study examines individuals in a sample, but does not try to influence the variable of interest.
Answer:
Option c
Step-by-step explanation:
The study is an observational study. An observational study is made when the researchers collect data based on what they see, hear or observe without any form of manipulation or treatment plan from the researchers. Thus, in this case, the study is an observational study because the study examines individuals in a sample, but does not try to influence the response variable/influence their responses.
To inspect manufacturing processes, companies typically examine samples of parts for deficiencies. One company that manufactures ballpoint pens selected samples of pens on each of days. The company recorded, for each sample of , the number of defective pens in the sample. Here are their data:
1, 1, 2, 2, 2, 2, 3, 5, 5, 6, 6, 6, 9, 11, 14, 15, 18
Required:
a. Which measures of central tendency do not exist for this data set?
b. Which measures of central tendency would be affected by the change?
c. Which of the following best describes the distribution of the original data?
d. Suppose that, starting with the original data set, the largest measurement were removed. Which measures of central tendency would be changed from those of the original data set?
Answer:
a. All measures exist
b. The Mean and the mode
c. Positively skewed
d. The mean and the median
Step-by-step explanation:
a. The frequencies of the data are;
1 2
2 4
3 1
5 2
6 3
9 1
11 1
14 1
15 1
18 1
The formula for mode is given as follows;
The mean = 108/17 = 6.35
The median of 1 1 2 2 2 2 3 5 5 6 6 6 9 11 14 15 18 = (n + 1)/2th term = 9th term
∴ The median = 5
The mode = 3×Median - 2 × Mean = 15 - 2 × 6.35 = 2.29
Hence all exist
The answer is none theses measures
b. Whereby 18 is replaced by 39 the mean will be then be
(108 + 39 - 18)/17 = 7.59
The median, which is the 9th term remain the same;
Hence only the mean and mode will be affected
c. Since more values are concentrated on the left side of the data distribution, the distribution is positively skewed
d. The largest measurement = 18 the 17th term
Removal will give
Mean = (108 - 18)/16 = 5.625 Mean changes
Median = (16 + 1)/2 th term = 8.5th term = 5 The median remains the same
The mode = 3(Mean - Median) changes
Therefore, the mean and the median will be changed.
Accident rate data y1, ...., y12 were collected over 12 consecutive years t=1,2,...12. At over 12 consecutive years t = 1,2,..., 12. At the end of the 6th year, a change in safety regulations occured. FOr each of the following situations, set up a linear model of the form y=XB+E. Define X and B appropriately.
a. The accident rate y is a linear function of t with the new safety regulations having no effect.
b. The accident rate y is a quadratic function of t with the new regulations having no effect.
c. The accident rate y is a linear function of t. The slope for t>= 7 is the same as for t<7. However there is a discrete jump for t=7.
d. The accident rate y is a linear function of t. After t=7, the slope changes, with the two lines intersecting at t=7.
Answer:
The correct option is;
The accident rate is a linear model function of t. After t = 7, the slope changes, with the two lines intersecting at t = 7
Step-by-step explanation:
The given parameters are;
Accident rate data = y₁, y₂, y₃, y₄, y₅, y₆, y₇, y₈, y₉, y₁₀, y₁₁, y₁₂
Time at which data was recorded = t₁, t₂, t₃, t₄, t₅, t₆, t₇, t₈, t₉, t₁₀, t₁₁, t₁₂
Accident rate equation is a linear model given as follows;
y = X·B + E
Where:
y = Accident rate
X = Slope of linear model
B = Year
E = y intercept of model
At the end of the 6th year, a change in a regulation that affects safety, hence accident rate occurred given as follows;
Before the change in safety regulations occurred for year t < 7 y₁ = X₁B + E₁
After the change in safety regulations occurred for year t < 7 y₂ = X₂B + E₂
Therefore the slope changes from X₁ to X₂ after t = 7 with the second linear model starting from the end of the first linear model making the two lines intersect at t = 7 (the beginning of year 7)
Hence the correct option is that "The accident rate is a linear model function of t. After t = 7, the slope changes, with the two lines intersecting at t = 7."
Please help. Only if you know how to do this . I’ll mark you as brainliest if correct.
[tex]answer \\ g(x) = |x - 2| + 1 \\ here \: f(x) = |x| \\ if \: we \: want \: to \: shift \: this \: function \: 2 \: \\ unit \: right \: then \: make \: transformation \\ \: of \: x \: by \: (x - 2) \\ and \: if \: we \: want \: to \: make \: function \: \\ goes \: up \: with \: 1 \: unit \: then \: transformation \\ is \: f(x) \: by \: f(x) + 1 \\ now \\ g(x) = |x - 2| + 1 \\ hope \: it \: helps[/tex]
At a computer store, a customer is considering 7 different computers, 9 different monitors, 8 different printers and 2 different scanners. Assuming that each of the components is compatible with one another and that one of each is to be selected, determine the number of different computer systems possible.
Answer:
1008
Step-by-step explanation:
to find the number of combinations, just multiply everything. you will get 1008 :)
Some cruise ship passengers are given magnetic bracelets, which they agree to wear in an attempt to eliminate or diminish the effects of motion sickness. Others are given similar bracelets that have no magnetism. What type of study is this? What are the variables of interest?
Choose the correct answer below.
A. Observational study. The variable of interest is whether the passenger experienced motion sickness.
B. Observational study. The variable of interest is whether a passenger's bracelet is magnetized or not.
C. Experiment. The variable of interest is whether the passenger experienced motion sickness.
D. Experiment. The variable of interest is whether a passenger's bracelet is magnetized or not.
Answer:
Option c
Step-by-step explanation:
This is an experiment because the researcher wants to test efficiency of the magnetic bracelets in the elimination of motion sickness i.e. whether they experienced motion sickness even after wearing the magnetic bracelets.