Answer:
Step-by-step explanation:
The mean of the reading points is
Mean = (5.8 + 5.9 + 4.9 + 5.2 + 5.0 + 4.9 + 6.2 + 5.1 + 5.7 + 6.1)/10 = 5.48
The process is out of control if the mean salt level of the readings is greater than 5.4
For the null hypothesis,
µ = 5.4
For the alternative hypothesis,
µ > 5.4
This is a right tailed test.
Since the population standard deviation is given, z score would be determined from the normal distribution table. The formula is
z = (x - µ)/(σ/√n)
Where
x = sample mean
µ = population mean
σ = population standard deviation
n = number of samples
From the information given,
µ = 5.4
x = 5.48
σ = 0.3
n = 10
z = (5.48 - 5.4)/(0.3/√10) = 0.84
Looking at the normal distribution table, the probability corresponding to the z score is 0.7996
The probability value to the right of the z score is 1 - 0.7996 = 0.2
Assuming a significance level of 0.05
Since alpha, 0.05 < than the p value, 0.2, then we would fail to reject the null hypothesis. Therefore, At a 5% level of significance, we can conclude that the process is not out of control. If we had rejected the null hypothesis, then our conclusion would be that the process is out of control.
All of the following are examples of quantitative data EXCEPT ________.
a. the amount of sleep normally gotten by the students in a class
b. the number of siblings that students have
c. the cholesterol levels of the students in a class
d. the exam scores for the students in a class
d. the gender of the students in a class
Answer:
e. the gender of the students in a class
Step-by-step explanation:
Quantitative data is measured is numbers. For example 1, 2, 3.5,...
Qualitative data are labels, that is, tall, short, male, female, Brazilian, Colombian,...
In this question:
The only data that is not measured in numbers is the gender of the studens in class, which can be male or female, they do not assume any numeric value. So the answer is e.
The quantitive data example does not include option e. the gender of the students in a class.
Data:Quantitative data is measured in numbers. like 1, 2, 3.5,..While on the other hand, Qualitative data are labels i.e. tall, short, male, female, etc. Based on this, the last option is correct.learn more about the data here: https://brainly.com/question/20296761
got another math problem.. please help
the correct answer is 59.
Answer:
59
Step-by-step explanation:
[2+ (4-2)+8²]-[2-(-1)][2+2+64]-[2-(-1)]²68-3²68-959Serena wants to determinethe area of the lawn the grass part of her front yard using the information given in the diagram below Serena knows that she needs to divide by 9 to change the units from square yards so she writes the expression below to determine the area of grass in square yards
Answer:
The answer is 295 square yards.
Step-by-step explanation:
[48(72-12)-15^2] divide by 9
3456-576-225 divide by 9
Subtract 3456 by 576
2880-255
2655 divide by 9
=295 square yards.
Hope this helped!
The answer is 295 square yards.
What is the area of square space?To find the area of square , take the square of side.
Given expression is [48(72-12)-15^2] divide by 9 .
Let the unknown area is x.
x = {48 * 60 - 15^2 } divide by 9
x = 2880 - 225 divide by 9
x = 2655 divide by 9
x =295 square yards.
Hence, The answer is 295 square yards.
To learn more about the area of square;
https://brainly.com/question/27776258
#SPJ2
Please answer this question I give brainliest thank you! Number 16
Answer:
4a
Step-by-step explanation:
The mean is found by adding all of the data set together and then dividing by the amount of individual pieces of data in the set.
(2+3+3+8) = 16
16/4=4
The answer is 4a.
brenna goes on a cave tour with her family.she spots a mysterious crystal that is shaped like a cube the crystal has edge lengths of 5 centimeters what is the volume of the crystal
Answer:
The volume of the crystal is [tex]V=125 \:cm^3[/tex].
Step-by-step explanation:
The volume enclosed by a cube is the number of cubic units that will exactly fill a cube.
To find the volume of a cube recall that a cube has all edges the same length. The volume of a cube is found by multiplying the length of any edge by itself three times. Or as a formula
[tex]V=s^3[/tex]
where:
s is the length of any edge of the cube.
From the information given we know that the crystal has edge lengths of 5 centimeters. Therefore, the volume of the crystal is
[tex]V=5^3=125 \:cm^3[/tex].
Jeanie wrote the correct first step to divide 8z2 + 4z – 5 by 2z.
Which shows the next step?
A.4z + 2 –
B.4z2 + 2 –
C.4z2 + 2 –
D.4z + 2 –
Answer:
4z + 2 - 5/2z
Step-by-step explanation:
8z^2 + 4z -5
divided by 2z
8z^2 /2z = 4z
4z/2z =2
5/2z = 5/2z
Putting them back together
4z + 2 - 5/2z
Answer:
A 4z + 2 - 5/2z
Step-by-step explanation:
A supervisor records the repair cost for 14 randomly selected refrigerators. A sample mean of $79.20 and standard deviation of $10.41 are subsequently computed. Determine the 90% confidence interval for the mean repair cost for the refrigerators. Assume the population is approximately normal. Step 1 of 2 : Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.
Answer:
( $74.623, $83.777)
The 90% confidence interval is = ( $74.623, $83.777)
Critical value at 90% confidence = 1.645
Step-by-step explanation:
Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.
The confidence interval of a statistical data can be written as.
x+/-zr/√n
Given that;
Mean x = $79.20
Standard deviation r = $10.41
Number of samples n = 14
Confidence interval = 90%
Using the z table;
The critical value that should be used in constructing the confidence interval.
z(α=0.05) = 1.645
Critical value at 90% confidence z = 1.645
Substituting the values we have;
$79.20+/-1.645($10.42/√14)
$79.20+/-1.645($2.782189528308)
$79.20+/-$4.576701774067
$79.20+/-$4.577
( $74.623, $83.777)
The 90% confidence interval is = ( $74.623, $83.777)
divide 41000 into two parts such that their amounts at 50% compound interest compounded annually in 2 and 3 years are equal
Answer:24600 , 16400
Step-by-step explanation:
Let the first part be x
So, second part will be 41000 - x
For amount x
SI = prt / 100
SI = x * 0.50 * 2
SI = 1x
For amount 41000 - x
SI = (41000-x) * 0.50 * 3
SI = 61500 - 1.5x
1x = 61500 - 1.5x
1.5x + x = 61500
2.5x = 61500
x = 61500 / 2.50 = 24600 for 2 years
2nd part = 41000 - 24600 = 16400 for three years
What is the difference of the polynomials? (–2x3y2 + 4x2y3 – 3xy4) – (6x4y – 5x2y3 – y5)
Answer:
-6x⁴y - 2x³y² + 9x²y³ - 3xy⁴ + y⁵
Step-by-step explanation:
(–2x³y² + 4x²y³ – 3xy⁴) – (6x⁴y – 5x²y³ – y⁵)=
–2x³y² + 4x²y³ – 3xy⁴ – 6x⁴y + 5x²y³ + y⁵=
-6x⁴y - 2x³y² + 9x²y³ - 3xy⁴ + y⁵
WILL MARK BRAINLIEST !!!
In the given point(-4,b) -4 is the x value.
Locate -4 on the graph and find the y value where the line is located. The y value would be b.
B = 1
Can someone please help me
Answer:
6
Step-by-step explanation:
Similar triangles. MNE is ABC but 3/4 the size. Multiply each side by 3/4 to get lengths.
x = 8 *3/4 = 6
Given the function g(x)=2∙3x+1, Find g−1 (x)
Answer:
[tex]g^{-1}(x)=\frac{x-1}{6}[/tex]
The following are daily outputs from shift A and shift B at a factory.
Shift A: {77, 91, 82, 68, 75, 72, 85, 65, 70, 79, 94, 86}
Shift B: {68, 93, 53, 100, 77, 86, 91, 88, 72, 74, 66, 82}
Q. Compare the means of the shift outputs. The workers in the shift with the highest mean will earn a bonus. Which shift will earn the bonus?
Answer:
shift B
Step-by-step explanation:
shift a is 78.6 repeating
shift b is 79.3 repeating
mean is when you add them all then divide it by the numbers it has
Answer:
shift B
Step-by-step explanation:
To calculate the mean for a set of data, add all the numbers in that set, then divide by the number of data points in the set.
A population of protozoa develops with a constant relative growth rate of 0.7781 per member per day. On day zero the population consists of six members. Find the population size after four days. (Round your answer to the nearest whole number.) P(4)
Answer:
[tex] P(t) = A (1+r)^t [/tex]
Where P represent the population after t days. a the initial amount on this case 6 and r the growth factor rate of 0.7781. so then our model would be given by:
[tex] P(t)= 6(1.7781)^t [/tex]
And replacing t=4 we got:
[tex] P(4) = 6(1.7781)^4 =59.975 \approx 60[/tex]
So then after 4 days we would expect about 60 protzoa
Step-by-step explanation:
For this case we can use the following function to model the population of protzoa:
[tex] P(t) = A (1+r)^t [/tex]
Where P represent the population after t days. a the initial amount on this case 6 and r the growth factor rate of 0.7781. so then our model would be given by:
[tex] P(t)= 6(1.7781)^t [/tex]
And replacing t=4 we got:
[tex] P(4) = 6(1.7781)^4 =59.975 \approx 60[/tex]
So then after 4 days we would expect about 60 protzoa
Can someone please help me on this?
Answer:
(0, 3/2)
Step-by-step explanation:
The equation can be put in the form ...
x^2 = 4py
where p = 3/2.
In this form, the focus is distance "p" from the vertex in the direction the parabola opens.
The vertex is at (0, 0); the parabola opens upward. So, the focus is 3/2 units above the vertex, at ...
focus = (0, 3/2) . . . . . matches choice A
A cell phone company
charges a $20 fee every
month and $0.01 for ten
minutes spent talking on
the phone. Write an
equation to model the cost
of a monthly cell phone bill
for the linear function.
Answer:
C = 20 + 0.001x
C = $20 + $0.001x
Step-by-step explanation:
Let x represent the number of minutes spent talking on the phone.
Given;
Fixed monthly charge F = $20
Charge per 10 minutes V = $0.01
Charge per minute = V/10 = $0.01/10 = $0.001
The equation to model the cost of a monthly cell phone bill;
Total cost = fixed cost + variable cost
C = F + (V/10)x
Substituting the values;
C = 20 + 0.001x
A statistics professor receives an average of five e-mail messages per day from students. Assume the number of messages approximates a Poisson distribution. What is the probability that on a randomly selected day she will have five messages
Answer:
The probability that on a randomly selected day the statistics professor will have five messages is 0.1755.
Step-by-step explanation:
Let the random variable X represent the number of e-mail messages per day a statistics professor receives from students.
The random variable is approximated by the Poisson Distribution with parameter λ = 5.
The probability mass function of X is as follows:
[tex]P(X=x)=\frac{e^{-5}\cdot 5^{x}}{x!};\ x=0,1,2,3...[/tex]
Compute the probability that on a randomly selected day she will have five messages as follows:
[tex]P(X=5)=\frac{e^{-5}\cdot 5^{5}}{5!}[/tex]
[tex]=\frac{0.006738\times 3125}{120}\\\\=0.17546875\\\\\approx 0.1755[/tex]
Thus, the probability that on a randomly selected day the statistics professor will have five messages is 0.1755.
x=(y+2)^2 solve the equation
Answer:
x= y^2+4y+4
Step-by-step explanation:
x= (y+2)(y+2)
x= y^2+2y+2y+4
x= y^2+4y+4
Answer:
X = y^2 + 4y + 4
Y= (√X) -2
Step-by-step explanation:
X = (Y+2)^2
X = (Y+2)(Y+2)
X = Y^2 + 4y + 4
X = (Y+2)^2
√X = √(Y+2)^2 (taking the root of both sides cancels the exponent)
√X = Y+2
-2 -2
(√X) - 2 = Y
or
Y = (√X) - 2
ASAP! GIVING BRAINLIEST! Please read the question THEN answer CORRECTLY! NO guessing. I say no guessing because people usually guess on my questions.
Answer:
D. F(x) = 2(x-3)^2 + 3
Step-by-step explanation:
We are told that the graph of G(x) = x^2, which is a parabola centered at (0, 0)
We are also told that the graph of the function F(x) resembles the graph of the function G(x) but has been shifted and stretched.
The graph of F(x) shown is facing up, so we know that it is multiplied by a positive number. This means we can eliminate A and C because they are both multiplied by -2.
Our two equations left are:
B. F(x) = 2(x+3)^2 + 3
D. F(x) = 2(x-3)^2 + 3
Well, we can see that the base of our parabola is (3, 3), so let's plug in the x value, 3, and see which equation gives us a y-value of 3.
y = 2(3+3)^2 + 3 =
2(6)^2 + 3 =
2·36 + 3 =
72 + 3 =
75
That one didn't give us a y value of 3.
y = 2(3-3)^2 + 3 =
2(0)^2 + 3 =
2·0 + 3 =
0 + 3 =
3
This equation gives us an x-value of 3 and a y-value of 3, which is what we wanted, so our answer is:
D. F(x) = 2(x-3)^2 + 3
Hopefully this helps you to understand parabolas better.
"A 12-foot ladder is leaning against a building. If the bottom of the ladder is sliding along the pavement directly away from the building at 33 feet/second, how fast is the top of the ladder moving down when the foot of the ladder is 55 feet from the wall?"
Answer:
Step-by-step explanation:
The question has typographical errors. The correct question is:
"A 12-foot ladder is leaning against a building. If the bottom of the ladder is sliding along the pavement directly away from the building at 3 feet/second, how fast is the top of the ladder moving down when the foot of the ladder is 5 feet from the wall?
Solution:
The ladder forms a right angle triangle with the ground. The length of the ladder represents the hypotenuse.
Let x represent the distance from the top of the ladder to the ground(opposite side)
Let y represent the distance from the foot of the ladder to the base of the wall(adjacent side)
The bottom of the ladder is sliding along the pavement directly away from the building at 3ft/sec. This means that y is increasing at the rate of 3ft/sec. Therefore,
dy/dt = 3 ft/s
The rate at which x is reducing would be
dx/dt
Applying Pythagoras theorem which is expressed as
Hypotenuse² = opposite side² + adjacent side², it becomes
x² + y² = 12²- - - - - - - -1
Differentiating with respect to time, it becomes
2xdx/dt + 2ydy/dt = 0
2xdx/dt = - 2ydy/dt
Dividing through by 2x, it becomes
dx/dt = - y/x ×dy/dt- - - - - - - - - - 2
Substituting y = 5 into equation 1, it becomes
x² + 5 = 144
x² = 144 - 25 = 119
x = √119 = 10.91
Substituting x = 10.91, dy/dt = 3 and y = 5 into equation 2, it becomes
dx/dt = - 5/10.91 × 3
dx/dt = - 1.37 ft/s
The following question involves a standard deck of 52 playing cards. In such a deck of cards there are four suits of 13 cards each. The four suits are: hearts, diamonds, clubs, and spades. The 26 cards included in hearts and diamonds are red. The 26 cards included in clubs and spades are black. The 13 cards in each suit are: 2, 3, 4, 5, 6, 7, 8, 9, 10, Jack, Queen, King, and Ace. This means there are four Aces, four Kings, four Queens, four 10s, etc., down to four 2s in each deck.
You draw two cards from a standard deck of 52 cards without replacing the first one before drawing the second. (a) Are the outcomes on the two cards independent? Why?
1. No. The events cannot occur together. 2. Yes. The events can occur together. 3. No. The probability of drawing a specific second card depends on the identity of the first card. 4. Yes. The probability of drawing a specific second card is the same regardless of the identity of the first drawn card.
(b) Find P(ace on 1st card and jack on 2nd). (Enter your answer as a fraction.)
(c) Find P(jack on 1st card and ace on 2nd). (Enter your answer as a fraction.)
(d) Find the probability of drawing an ace and a jack in either order. (Enter your answer as a fraction.)
Answer:
(a)No. The probability of drawing a specific second card depends on the identity of the first card.
(b)4/663
(c) 4/663
(d) 8/663
Step-by-step explanation:
(a)The events are not independent because we are drawing cards without replacement and the probability of drawing a specific second card depends on the identity of the first card.
(b) P(ace on 1st card and jack on 2nd).
[tex]P$(Ace on 1st card) =\dfrac{4}{52}\\ P$(Jack on 2nd card)=\dfrac{4}{51}\\\\$Therefore:\\P(ace on 1st card and jack on 2nd) =\dfrac{4}{52}\times \dfrac{4}{51}\\=\dfrac{4}{663}[/tex]
(c)P(jack on 1st card and ace on 2nd)
[tex]P$(Jack on 1st card) =\dfrac{4}{52}\\ P$(Ace on 2nd card)=\dfrac{4}{51}\\\\$Therefore:\\P(jack on 1st card and ace on 2nd) =\dfrac{4}{52}\times \dfrac{4}{51}\\=\dfrac{4}{663}[/tex]
(d)Probability of drawing an ace and a jack in either order.
We can either draw an ace first, jack second or jack first, ace second.
Therefore:
P(drawing an ace and a jack in either order) =P(AJ)+(JA)
From parts (b) and (c) above:
[tex]P$(jack on 1st card and ace on 2nd) =\dfrac{4}{663}\\P$(ace on 1st card and jack on 2nd) =\dfrac{4}{663}\\$Therefore:\\P(drawing an ace and a jack in either order)=\dfrac{4}{663}+\dfrac{4}{663}\\=\dfrac{8}{663}[/tex]
Louis had 19 dogs. He feeds them with 38 pounds of biscuits. If there are 4 more
dogs, then how much more pounds of biscuit are needed?
Answer:
14
Step-by-step explanation:
Answer:
Which of these factors will affect the friction on a road
Step-by-step explanation:
Solve the inequality and graph the solution set. Write the answer in interval notation. Write your answer in exact simplified form
0> 20x+2>-32
what is the solution?
Answer:
The solution is [tex]\:\left(-\frac{17}{10},\:-\frac{1}{10}\right)[/tex].
Step-by-step explanation:
An inequality is a mathematical relationship between two expressions and is represented using one of the following:
≤, "less than or equal to"<, "less than">, "greater than" ≥, "greater than or equal to"To find the solution of the inequality [tex]0>\:20x+2>\:-32[/tex] you must:
[tex]\mathrm{If}\:a>u>b\:\mathrm{then}\:a>u\quad \mathrm{and}\quad \:u>b\\\\0>20x+2\quad \mathrm{and}\quad \:20x+2>-32[/tex]
First, solve [tex]0>20x+2[/tex]
[tex]\mathrm{Switch\:sides}\\\\20x+2<0\\\\\mathrm{Subtract\:}2\mathrm{\:from\:both\:sides}\\\\20x+2-2<0-2\\\\\mathrm{Simplify}\\\\20x<-2\\\\\mathrm{Divide\:both\:sides\:by\:}20\\\\\frac{20x}{20}<\frac{-2}{20}\\\\\mathrm{Simplify}\\\\x<-\frac{1}{10}[/tex]
Next, solve [tex]20x+2>-32[/tex]
[tex]20x+2-2>-32-2\\\\20x>-34\\\\\frac{20x}{20}>\frac{-34}{20}\\\\x>-\frac{17}{10}[/tex]
Finally, combine the intervals
[tex]x<-\frac{1}{10}\quad \mathrm{and}\quad \:x>-\frac{17}{10}\\\\-\frac{17}{10}<x<-\frac{1}{10}[/tex]
The interval notation is [tex]\:\left(-\frac{17}{10},\:-\frac{1}{10}\right)[/tex] and the graph is:
7+2x/3=5 im stuck on this question pls hhelp my homework is due soon pls help
The value of X is 4
please see the attached picture for full solution
Hope it helps
Good luck on your assignment..
Write the standard form of a circle with a center at C(-4, -6) and passes through the point (-1, -2).
Answer:
(x+4)^2+(y+6)^2 = 25
Step-by-step explanation:
The radius squared is equal to the distance between the center and the point
3^2 + 4^2 = 25
We can shift the center like this
(x+4)^2+(y+6)^2 = 25
Two barrels are mathematically similar
The smaller barrel has a height of [tex]h[/tex]cm and a capacity of 100 Liters
The larger barrel has a height of 90cm and a capacity of 160 Liters
-Work out the value of [tex]h[/tex]
Answer:
h ≈ 77 cm
Step-by-step explanation:
Let us convert the liters to cm³.
Smaller barrel
0.001 litres = 1 cm³
100 litres = 100000 cm³
Larger barrel
0.001 litres = 1 cm³
160 litres = 160000 cm³
For a similar solid figure the cube of their corresponding sides is equal to the volume ratio.
This means
h³/90³ = 100000/160000
cube root both sides
h/90 = ∛100000 / ∛160000
h/90 = 46.4158883/54.2883523
cross multiply
54.2883523h = 46.4158883 × 90
54.2883523h = 4177.429947
divide both side by 54.2883523
h = 4177.429947/54.2883523
h = 76.9489175858
h ≈ 77 cm
A car rental company charges a daily rate of $35 plus $0.20 per mile for a certain car. Suppose that you rent that car for a day and your bill (before taxes) is $97. How many miles did you drive?
Answer:
360 miles
Step-by-step explanation:
97= 25+0.2m0.2m= 97-250.2m= 72m= 72/0.2m= 360 miles A box plot is shown below:
What is the median and Q1 of the data set represented on the plot?
Median = 31; Q1 = 26
Median = 30; Q1 = 26
Median = 31; Q1 = 20
Median = 30; Q1 = 20
Answer:
Step-by-step explanation:
Hello!
I didn't find the exact box plot for this exercise but I've found one that'll help you identify the required values
When constructing a box plot the box lower and upper limits are defined by the first and third quartiles and the line separating it in two represents the median.
In this case, the box is lying on the side, the first quartile is represented by the left side of the box. If you see the graphic this one corresponds to 25.
The median, as said, is represented by the line drawn inside the box, it is not necessarily in its middle but it will always be inside it.
Watching the example, the median is 33
I hope this helps!
Answer: D
Step-by-step explanation:
Solve the system of equations.
3x + 3y + 6z = 6
3x + 2y + 4z = 5
7x + 3y + 32 = 7
a. (x = 2, y = -2, z = 0)
b. (x = 3, y=-3, z = 3)
c. (x = 1, y = - 1,2= 1)
d. (x = 0, y = 0, z = 2)
Answer:
The answer is option c
x = 1 y = - 1 z = 1
Hope this helps.
In a study of the relationship of the shape of a tablet to its dissolution time, 6 disk-shaped ibuprofen tablets and 8 oval-shaped ibuprofen tablets were dissolved in water. The dissolve times, in seconds, were as follows:
Disk: 269.0, 249.3, 255.2, 252.7, 247.0, 261.6
Oval: 268.8, 260.0, 273.5, 253.9, 278.5, 289.4, 261.6, 280.2 Can you conclude that the mean dissolve times differ between the two shapes? Conduct a hypothesis test at the
α = 5% level.
a. State the appropriate null and alternative hypotheses.
b. Compute the test statistic.
c. Compute the P-value.
d. State the conclusion of the test in the context of this setting.
Answer:
Step-by-step explanation:
This is a test of 2 independent groups. Let μ1 be the mean dissolution time for disk-shaped ibuprofen tablets and μ2 be the mean dissolution time for oval-shaped ibuprofen tablets.
The random variable is μ1 - μ2 = difference in the mean dissolution time for disk-shaped ibuprofen tablets and the mean dissolution time for oval-shaped ibuprofen tablets.
We would set up the hypothesis.
a) The null hypothesis is
H0 : μ1 = μ2 H0 : μ1 - μ2 = 0
The alternative hypothesis is
H1 : μ1 ≠ μ2 H1 : μ1 - μ2 ≠ 0
This is a two tailed test.
For disk shaped,
Mean, x1 = (269.0 + 249.3 + 255.2 + 252.7 + 247.0 + 261.6)/6 = 255.8
Standard deviation = √(summation(x - mean)²/n
n1 = 6
Summation(x - mean)² = (269 - 255.8)^2 + (249.3 - 255.8)^2 + (255.2 - 255.8)^2+ (252.7 - 255.8)^2 + (247 - 255.8)^2 + (261.6 - 255.8)^2 = 337.54
Standard deviation, s1 = √(337.54/6) = 7.5
For oval shaped,
Mean, x2 = (268.8 + 260 + 273.5 + 253.9 + 278.5 + 289.4 + 261.6 + 280.2)/8 = 270.7375
n2 = 8
Summation(x - mean)² = (268.8 - 270.7375)^2 + (260 - 270.7375)^2 + (273.5 - 270.7375)^2+ (253.9 - 270.7375)^2 + (278.5 - 270.7375)^2 + (289.4 - 270.7375)^2 + (261.6 - 270.7375)^2 + (280.2 - 270.7375)^2 = 991.75875
Standard deviation, s2 = √(991.75875/8) = 11.1
b) Since sample standard deviation is known, we would determine the test statistic by using the t test. The formula is
(x1 - x2)/√(s1²/n1 + s2²/n2)
Therefore,
t = (255.8 - 270.7375)/√(7.5²/6 + 11.1²/8)
t = - 3
c) The formula for determining the degree of freedom is
df = [s1²/n1 + s2²/n2]²/(1/n1 - 1)(s1²/n1)² + (1/n2 - 1)(s2²/n2)²
df = [7.5²/6 + 11.1²/8]²/[(1/6 - 1)(7.5²/6)² + (1/8 - 1)(11.1²/8)²] = 613.86/51.46
df = 12
We would determine the probability value from the t test calculator. It becomes
p value = 0.011
d) Since alpha, 0.05 > than the p value, 0.011, then we would reject the null hypothesis. Therefore, we can conclude that at 5% significance level, the mean dissolve times differ between the two shapes