QUESTION 1

A random sample of 8 subjects was selected for estimating the average body mass index (BMI) for a certain population. The sample measurements are: 21, 23, 25, 20, 27, 29, 31, 26 Normality assumption is acceptable based on normality test. Which of the following statement is correct, if one wishes to test whether the average BMI for this population is different from 23 at 5% level of significance using one sample t-test.

	A.	The t-test statistic value is 25.25.
	B.	The t-test statistic value is 0.12.
	C.	The t-test statistic value is -1.67.
	D.	The t-test statistic value is 1.67.

4 points

QUESTION 2

A random sample of 8 subjects was selected for estimating the average body mass index (BMI) for a certain population. The sample measurements are: 21, 23, 25, 20, 27, 29, 31, 26 Normality assumption is acceptable based on normality test. Which of the following statements is correct, if one wishes to test whether the average BMI for this population is less than 23 at 5% level of significance using one sample t-test. Use statistical softwareto perform the test for getting p-value.

	A.	The p-value of the test is .861.
	B.	The p-value of the test is .0695.
	C.	The p-value of the test is .9305.
	D.	The p-value of the test is .139.

4 points

QUESTION 3

A researcher wishes to test a hypothesis, using a 5% level of significance, to see if the average level of cholesterol level (LDL) can be reduced from using a medical treatment for a particular population. If one wishes to perform an one-sided one-sample t-test, and wishes that the test to have a power of .80 to detect a reduction of 10 mg/100ml in cholesterol level (LDL), how large a sample would be needed? (From a pilot study, the estimated standard deviation of the cholesterol levels of this population is 30.)

	A.	56
	B.	77
	C.	71
	D.	116

4 points

QUESTION 4

The following random sample of 6 observations was collected for testing whether the average time spent in moderate exercise of a population per week is different from 4 hours or not. 5 6 6 2 9 7 Perform the test at 5% level of significance. Use statistical software to perform all the tests and computations. (There are two correct choices. No partial credit for this question.)

	A.	The standard error of the mean in this test is 2.32.
	B.	Thenormality test from statistical softwareused for our class wouldsuggest that the normality is an acceptable assumption for this data.
	C.	The p-value of this test is less than 0.05.
	D.	There is no statistically significant evidence to support that the average hours of exercise per week for this population is different from 4.

4 points

QUESTION 5

In a random sample from a population, 280 out of the sample of 500 subjects responded "Yes" to a survey question. Researchers used this data to test whether the percentage of people in this population who would vote for "Yes" is different from 55%, at 5% level of significance using Chi-square goodness of fit test. Which of the followings are correct? (There are two correct choices. No partial credit for this question.)

	A.	The p-value from the test is 0.008.
	B.	The p-value from the test is 0.653.
	C.	There is sufficient evidence to support that the percentage of people in this population who would vote for "Yes" is different from 55%,
	D.	There is no sufficient evidence to support that the percentage of people in this population who would vote for "Yes" is different from 55%,

5 points

QUESTION 6

In a random sample from a population, 280 out of the sample of 500 subjects responded "Yes" to a survey question. Researchers used this data to test whether the percentage of people in this population who would vote for "Yes" isgreater than 55%, at 5% level of significance usingZ-test for proportion. Which of the followings are correct p-value?

	A.	0.653
	B.	0.004
	C.	0.327
	D.	0.673