Question 1 of 17

Two independent samples of sizes n₁ = 50 and n₂ = 50 are randomly selected from two populations to test the difference between the population means, . The sampling distribution of the sample mean difference, is:

A.approximately normal
B.chi-squared distributed with 99 degrees of freedom
C.t - distributed with 98 degrees of freedom
D.normally distributed

Reset Selection

Question 2 of 17

Some defendants in criminal proceedings plead guilty and are sentenced without a trial, whereas others who plead innocent are subsequently found guilty and then are sentenced. In recent years, legal scholars have speculated as to whether sentences of those who plead guilty differ in severity from sentences for those who plead innocent and are subsequently judged guilty. Consider the data given below on defendants accused of robbery, all of whom, by the way, had previous prison records. At the .01 level of significance, do these data suggest that the proportion of all defendants in these circumstances who plead guilty and are sent to prison differs from the proportion who are sent to prison after pleading innocent and being found guilty?

	Plea
	Guilty	Not Guilty
Number judged guilty	n1 = 191	n2 = 64
Number sentenced to prison	x1 = 101	x2 = 56
Sample proportion	.529	.875

A.Yes, because the test value -4.94 is outside the interval (-2.58, 2.58)
B.Yes, because the test value 2.58 is inside the interval (-4.94, 4.94)
C.No, because the test value -4.94 is outside the interval (-1.96, 1.96)
D.No, because the test value -1.96 is inside the interval (-2.58, 2.58)

Reset Selection

Question 3 of 17

Members of the general adult population volunteer an average of 4.2 hours per week. A random sample of 20 female college students and 18 male college students produced the results given in the table below. At the .01 level of significance, is there sufficient evidence to conclude that a difference exists between the mean number of volunteer hours per week for male and female college students?

	Females	Males
Sample size	20	18
Sample mean	3.8	2.5
Sample variance	3.5	2.2

A.No, because the test value 2.38 is greater than the critical value
B.No, because the test value 2.38 does not exceed the critical value
C.No, because the test value 2.90 is greater than the critical value
D.Yes, because the test value 2.90 is greater than the critical value

Reset Selection

Part 2 of 8 -

Question 4 of 17

The regression line y' = -3 + 2.5 X has been fitted to the data points (28, 60), (20, 50), (10, 18), and (25, 55). The sum of the squared residuals will be:

A.49.00
B.16.00
C.20.25
D.94.25

Reset Selection

Question 5 of 17

In regression analysis, the variable we are trying to explain or predict is called the

A.independent variable
B.regression variable
C.dependent variable
D.residual variable

Reset Selection

Question 6 of 17

Outliers are observations that

A.lie outside the sample
B.render the study useless
C.lie outside the typical pattern of points
D.disrupt the entire linear trend

Reset Selection

Question 7 of 17

In a simple linear regression analysis, the following sum of squares are produced: = 500 = 100 = 400 The proportion of the variation in Y that is explained by the variation in X is:

A.25%
B.50%
C.80%
D.20%

Reset Selection

Question 8 of 17

Data for a sample of 25 apartments in a particular neighborhood are provided in the worksheet Apartments in the Excel workbook Apartments.xlsx. Using that data, find the estimated regression equation which can be used to estimate the monthly rent for apartments in this neighborhood using size as the predictor variable. Apartments.xlsx

Rent	Size
950	850
1600	1450
1200	1085
1500	1232
950	718
1700	1485
1650	1136
935	726
875	700
1150	956
1400	1100
1650	1285
2300	1985
1800	1369
1400	1175
1450	1225
1100	1245
1700	1259
1200	1150
1150	896
1600	1361
1650	1040
1200	755
800	1000
1750	1200

A.197.12 + 2.065(size)
B. 177.12 + 1.065(size)
C.177.12 + 0.8500(size)
D.1.065 + 177.12(size)

Reset Selection

Part 3 of 8 -

Question 9 of 17

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A field researcher is gathering data on the trunk diameters of mature pine and spruce trees in a certain area. The following are the results of his random sampling. Can he conclude, at the 0.10 level of significance, that the average trunk diameter of a pine tree is greater than the average diameter of a spruce tree?

	Pine trees	Spruce trees
Sample size	20	30
Mean trunk diameter (cm)	45	39
Sample variance	100	150

What is the test value for this hypothesis test? Test value: Round your answer to three decimal places. What is the critical value? Critical value: Round your answer to three decimal places.

Part 4 of 8 -

Question 10 of 17

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A company has observed that there is a linear relationship between indirect labor expense (ILE) , in dollars, and direct labor hours (DLH). Data for direct labor hours and indirect labor expense for 18 months are given in the file ILE_and_DLH.xlsx

DLH(X)	ILE(Y)
20	361
25	400
22	376
23	384
20	361
19	360
24	427.2
28	458.4
26	450.8
29	475.2
27	462.6
25	445
28	511
32	550.8
35	587.8
34	574.1
30	535.4
36	591.5

Treating ILE as the response variable, use regression to fit a straight line to all 18 data points. Using your estimated regression output, predict the indirect labor expenses for a month in which the company has 31 direct labor hours. Place your answer, rounded to 1 decimal place, in the blank. Do not use any stray punctuation marks or a dollar sign. For example, 458.9 would be a legitimate entry.

Question 11 of 17

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A company has observed that there is a linear relationship between indirect labor expense (ILE) , in dollars, and direct labor hours (DLH). Data for direct labor hours and indirect labor expense for 18 months are given in the file ILE_and_DLH.xlsx

DLH(X)	ILE(Y)
20	361
25	400
22	376
23	384
20	361
19	360
24	427.2
28	458.4
26	450.8
29	475.2
27	462.6
25	445
28	511
32	550.8
35	587.8
34	574.1
30	535.4
36	591.5

Treating ILE as the response variable, use regression to fit a straight line to all 18 data points. Based on your results, If direct labor hours (DLH) increases by one hour, the indirect labor expense (ILE), on average, increases by approximately how much? Place your answer, rounded to 2 decimal places, in the blank. Do not use any stray punctuation marks or a dollar sign. For example, 34.56 would be a legitimate entry.

Part 5 of 8 -

Question 12 of 17

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Are America's top chief executive officers (CEOs) really worth all that money? One way to answer this question is to look at the annual company percentage increase in revenue versus the CEO's annual percentage salary increase in that same company. Suppose that a random sample of companies yielded the following data:

percent change for corporation	15	12	3	12	28	6	8	2
percent change for CEO	6	17	-4	12	32	-1	7	2

Do these data indicate that the population mean percentage increase in corporate revenue is greater than the population mean percentage increase in CEO salary? Use a 5% level of significance. What is the p-value associated with this test of hypothesis? Place your answer, rounded to 3 decimal places, in the blank. For example, 0.134 would be a legitimate entry.

Question 13 of 17

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Q-Mart is interested in comparing its male and female customers. Q-Mart would like to know if the amount of money spent by its female charge customers differs, on average, from the amount spent by its male charge customers. To answer this question, an analyst collected random samples of 25 female customers and 22 male customers. Based on these samples, on average, the 25 women charge customers spent $102.23 and the 22 men charge customers spent $86.46. Moreover, the sample standard deviation of the amount charged by the 25 women was $93.393, and the sample standard deviation of the amount charged by the 22 men was $59.695. Suppose, using a 10% level of significance, you wish to know if there is sufficient evidence for Q-Mart to conclude that, on average, the amount spent by women charge customers differs from the amount spent by men charge customers. That is suppose you wish to test H₀: versus H₁: Assuming that the amounts spent by male and female charge customers at Q-Mart are normally distributed, based on the procedure advocated by Bluman, what is the test value that you would use to conduct this test of hypothesis? Place your answer, rounded to 3 decimal places, in the blank. For example, 0.123 would be a legitimate entry.

Part 6 of 8 -

Question 14 of 17

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A special coating is applied to several scale model engine nacelle body shapes to determine if it reduces the drag coefficient. The following data are the drag coefficient before the coating is applied and after.

Model	#1	#2	#3	#4	#5	#6
Before	0.782	0.656	0.541	0.250	0.323	0.888
After	0.668	0.581	0.532	0.241	0.334	0.891

Perform a hypothesis test to determine if there is evidence at the 0.05 level of significance to support the claim that the coating reduces the drag coefficient. What is the test value for this hypothesis test? Answer: Round your answer to two decimal places. What is the P-value for this hypothesis test? Answer: Round your answer to three decimal places. What is your conclusion for this test? Choose one. 1. There is sufficient evidence to show the coating reduces the drag coefficient. 2. There is not sufficient evidence to show that the coating reduces the drag coefficient. 3. There is sufficient evidence to show that the drag coefficient changed after the coating was applied. 4. There is sufficient evidence to show that the drag coefficient increased after the coating was applied. Answer: Enter only a 1, 2, 3 or 4 for your answer.

Part 7 of 8 -

Question 15 of 17

In conducting hypothesis testing for difference between two means when samples are dependent (paired samples), the variable under consideration is ; the sample mean difference between the pairs.

True

False

Reset Selection

Part 8 of 8 -

Question 16 of 17

When the actual values y of a response variable and the corresponding predicted values y' are the same, the standard error of the estimate will be zero.

True

False

Reset Selection

Question 17 of 17

In a simple linear regression problem, the least squares line is y' = -3.2 + 1.3X, and the coefficient of determination is 0.7225. The coefficient of correlation must be 0.85.

True

False