| Question 1 of 17 |
1.0 Points |
A pharmaceutical company is testing the effectiveness of a new drug for lowering cholesterol. As part of this trial, they wish to determine whether there is a difference between the effectiveness for women and for men. Assume α = 0.05. What is the test value?
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Women |
Men |
| Sample size |
50 |
80 |
| Mean effect |
7 |
6.95 |
| Sample variance |
3 |
4 |
| A.t = 0.151 |
| B.z = 0.081 |
| C.t = 3.252 |
| D.z = 0.455 |
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| Question 2 of 17 |
1.0 Points |
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?
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Plea |
| |
Guilty |
Not Guilty |
| Number judged guilty |
n1 = 191 |
n2 = 64 |
| Number sentenced to prison |
x1 = 101 |
x2 = 56 |
| Sample proportion |
.529 |
.875 |
| A.No, because the test value -1.96 is inside the interval (-2.58, 2.58) |
| B.No, because the test value -4.94 is outside the interval (-1.96, 1.96) |
| C.Yes, because the test value 2.58 is inside the interval (-4.94, 4.94) |
| D.Yes, because the test value -4.94 is outside the interval (-2.58, 2.58) |
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| Question 3 of 17 |
1.0 Points |
Which of the following statements is true regarding the F – distribution?
| A.It is a distribution of negative values |
| B.It is always skewed to the left |
| C.It typically appears in tests of equal proportions |
| D.none of the above |
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| Question 4 of 17 |
1.0 Points |
An agent for a residential real estate company in a large city would like to be able to predict the monthly rental cost of apartments based on the size of the apartment. Data for a sample of 25 apartments in a particular neighborhood are provided in the worksheet Apartments in the Excel workbook Apartments.xlsx.
Apartments.xlsx
At the .05 level of significance determine if the correlation between rental cost and apartment size is significant.
| A.Yes, there is a statistically significant linear relationship between monthly rental cost and apartment size, because the sample correlation coefficient 0.85 exceeds 0.50. |
| B.Yes, there is a statistically significant linear relationship between monthly rental cost and apartment size, because the t-test value, 7.74, is greater than the critical value 1.96. |
| C.Yes, there is a statistically significant linear relationship between monthly rental cost and apartment size, because the p-value for this test is less than .0001. |
| D.No, there is not a statistically significant linear relationship between monthly rental cost and apartment size, because the sample correlation coefficient is less than .95. |
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| Question 5 of 17 |
1.0 Points |
A correlation value of zero indicates.
| A.a weak linear relationship |
| B.a perfect linear relationship |
| C.a strong linear relationship |
| D.no linear relationship |
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| Question 6 of 17 |
1.0 Points |
If an estimated regression line has a Y-intercept of –7.5 and a slope of 2.5, then when X = 3, the actual value of Y is:Reset Selection |
| Question 7 of 17 |
1.0 Points |
The standard error of the estimate, sest, is essentially the
| A.mean of the explanatory variable |
| B.mean of the residuals |
| C.standard deviation of the residuals |
| D.standard deviation of the explanatory variable |
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| Question 8 of 17 |
1.0 Points |
A linear regression analysis produces the equation
y = 5.32 + (-0.846)x
Which of the following statements must be true?
| A.As x increases, y decreases, and the correlation coefficient must be positive. |
| B.As x increases, y decreases, and the correlation coefficient must be negative. |
| C.As x increases, y increases, and the correlation coefficient must be positive. |
| D.As x increases, y increases, and the correlation coefficient must be negative. |
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| Question 9 of 17 |
2.0 Points |
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 |
25 |
35 |
| Mean trunk diameter (cm) |
55 |
48 |
| Sample variance |
100 |
140 |
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.
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| Question 10 of 17 |
1.0 Points |
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
Treating ILE as the response variable, use regression to fit a straight line to all 18 data points. What values for the intercept (a) and slope (b) do you obtain?
Place your answers, rounded to 3 decimal places, in the blanks provided. Do not use any stray punctuation marks. For example, 34.567 would be a legitimate entry.
intercept (a) =
slope(b) =
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| Question 11 of 17 |
1.0 Points |
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
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.
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| Question 12 of 17 |
1.0 Points |
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 critical value that you would use to conduct this test of hypothesis? Place your answer, rounded to 3 decimal places, in the blank. For example, 2.345 would be a legitimate entry.
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| Question 13 of 17 |
1.0 Points |
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.
An investor wants to compare the risks associated with two different stocks. One way to measure the risk of a given stock is to measure the variation in the stock’s daily price changes.
In an effort to test the claim that the variance in the daily stock price changes for stock 1 is different from the variance in the daily stock price changes for stock 2, the investor obtains a random sample of 21 daily price changes for stock 1 and 21 daily price changes for stock 2.
The summary statistics associated with these samples are: n1 = 21, s1 = .848, n2 = 21, s2 = .529.
If you follow Bluman’s advice and place the larger variance in the numerator when computing the test value, at the .05 level of significance, what is the critical value associated with this test of hypothesis? Place your answer, rounded to 2 decimal places, in the blank. For example, 3.45 would be a legitimate entry.
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| Question 14 of 17 |
3.0 Points |
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.
Researchers conducted an experiment to measure the effect of a drug on improving the quality of sleep as determined by how many more minutes of REM sleep were measured for each participant. One group of participants were given the experimental drug; the other (control) group was given a placebo. Does the evidence indicate that the drug improved the amount of REM sleep at a 0.01 level of significance? Answer each of the following parts.
| |
Experimental group |
Control group |
| sample size |
35 |
50 |
| mean sleep improvement |
12.8 |
9.1 |
| sample variance |
56.3 |
61.2 |
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 the conclusion of this hypothesis test? Choose one.
1. There is sufficient evidence to show that the experimental drug improved the quality of sleep.
2. There is not sufficient evidence to show that the experimental drug improved the quality of sleep.
3. There is sufficient evidence to show that the quality of sleep is different for the experimental drug than for the control drug.
4. There is not sufficient evidence to show that the control drug decreased the quality of sleep.
Answer: Enter only a 1, 2, 3 or 4 for your answer.
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| Question 15 of 17 |
1.0 Points |
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.Reset Selection |
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| Question 16 of 17 |
1.0 Points |
In simple linear regression analysis, the relationship between the response variable Y and the explanatory variable X is a straight line. This means that all data points lie on the line.Reset Selection |
| Question 17 of 17 |
1.0 Points |
In a simple regression analysis, if the standard error of estimate sest = 15 and the number of observations n = 10, then the sum of the residuals squared must be 120. |
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