4



IT IS CRITICAL TO NOTE THAT WHEN GIVEN THIS EXAM, STUDENTS WERE EXPECTED TO USE THE TABLES TO FIND CRITICAL VALUES AND P-VALUES. WE NO LONGER REQUIRE THIS, SO DON’T BE SPOOKED BY QUESTIONS THAT INCORPORATE THAT COMPONENT. DESPITE THIS DRAWBACK, THE QUESTIONS ARE REPRESENTATIVE OF THE KNOWLEDGE BASE AND TYPE OF QUESTIONS WE TYPICALLY ASK. YOU SHOULD EXPECT TO SEE QUESTIONS WHICH UTILIZE EXCEL OUTPUT IN YOUR MID-TERM.

ALSO NOTE THAT DUE TO THE VARIATION IN CHAPTER COVERAGE, THERE ARE NO QUESTIONS ON THIS PRACTICE EXAM INVOLVING CHAPTER 17—THERE WILL BE ON YOUR EXAM, AND THERE ARE NUMEROUS QUESTIONS DELETED AS THEY WERE COVERING CHAPTERS THAT WE DID NOT INCLUDE THIS SEMESTER.

ANSWERS ARE INCLUDED FOR ALL QUESTIONS.

1. If the value of the sample mean [pic] is close enough to the hypothesized value of the population mean [pic], then:

a. the hypothesized value is definitely true

b. the hypothesized value is definitely false

c. we reject the null hypothesis

d. we don’t reject the null hypothesis

ANSWER: d

2. In testing the null hypothesis [pic], if [pic] is false, the test could lead to:

a. a Type I error

b. a Type II error

c. either a Type I or a Type II error

d. None of the above

ANSWER: b

4. If we reject the null hypothesis, we conclude that :

a. there is enough statistical evidence to infer that the alternative hypothesis is true

b. there is not enough statistical evidence to infer that the alternative hypothesis is true

c. there is enough statistical evidence to infer that the null hypothesis is true

d. the test is statistically insignificant at whatever level of significance the test was conducted at

ANSWER: a

5. After testing the hypothesis below at the 5% significance level

[pic]

[pic]

given that a random sample of 10 observations was drawn from a normal population, and the sample standard deviation was .043, you should conclude:

a. The Test Statistic = 2.334, and you should reject H0.

b. The Test Stastic = 2.334, and you should not rejet H0.

c. The Test Statistic = 1.664, and you should not reject H0.

d. The Test Statistic = 1.664, and you should reject H0.

ANSWER: d

7. In testing the hypotheses

[pic]50

[pic]50

the following information is known: n = 64, [pic]= 53.5, and s = 10. The standardized test statistic equals:

a. 1.96

b. –2.8

c. 2.8[pic]

d. –1.96

ANSWER: c

9. There are three politicians who are attempting to win the Democratic nomination for senator. In a survey of 1,000 Democrats, candidate A is favored by 550 people, candidate B is supported by 300 people, and the remaining 150 respondents favor candidate C. If you tested whether these results provide enough statistical evidence at the 1% significance level to indicate that candidate A will receive at least 50% of the vote, the value of your Test Statistic would be:

a. 3.16

b. –3.16

c. 2.84

d. –2.84

ANSWER: a

10. Which of the following are measures of the linear relationship between two variables?

a. The covariance

b. The coefficient of correlation

c. The variance

d. Both a and b

ANSWER: d

12. The Empirical Rule states that the approximate percentage of measurements in a data set (providing that the data set has a bell-shaped distribution) that fall within two standard deviations of their mean is approximately:

a. 68%

b. 75%

c. 95%

d. 99%

ANSWER: c

13. In the formula [pic], the [pic]refers to:

a. the probability that the confidence interval will contain the population mean

b. the probability that the confidence interval will not contain the population mean

c. the area in the lower tail or upper tail of the sampling distribution of the sample mean

d. the level of confidence

ANSWER: c

14. Random samples from two normal populations produced the following statistics:

[pic] 10 [pic]32

[pic]15 [pic]22

In testing whether there is enough evidence at the 10% significance level to infer that the variance of population 1 is different than the variance of population 2, your test statistic value is:

a. 2.133

b. 0.6875

c. 1.50

d. 1.455

ANSWER: d

16. An investor is considering two types of investment. She is satisfied that the expected return on investment 1 is higher than the expected return on investment 2. However, she is concerned that the risk associated with investment 1 is higher than that of investment 2. To help make her decision, she randomly selects seven monthly returns on investment 1 and ten monthly returns on investment 2. She finds that the sample variances of investments 1 and 2 are 225 and 118, respectively. Can she infer at the 5% significance level that the population variance of investment 1 exceeds that of investment 2?

a. No, they appear equal with a test statistic value of 1.907.

b. No, they appear unequal with a test statistic value of 1.907.

c. Yes, they appear equal with a test statistic value of 2.065.

d. Yes, they appear unequal with a test statistic value of 2.065.

ANSWER: a

17. In constructing 95% confidence interval estimate for the difference between the means of two normally distributed populations, where the unknown population variances are assumed not to be equal, summary statistics computed from two independent samples are as follows:

[pic] [pic] [pic]

[pic] [pic] [pic]

The upper confidence limit is:

a. 19.123

b. 28.212

c. 24.911

d. 5.788

ANSWER: b

22. Generally speaking, if two variables are unrelated (as one increases, the other shows no pattern), the covariance will be

a. a large positive number

b. a large negative number

c. a positive or negative number close to zero

d. none of the above

ANSWER: c

23. A Type II error is defined as:

a. rejecting a true null hypothesis

b. rejecting a false null hypothesis

c. not rejecting a true null hypothesis

d. not rejecting a false null hypothesis

ANSWER: d

25. In selecting the sample size to estimate the population proportion p, if we have no knowledge of even the approximate values of the sample proportion [pic], we:

a. take another sample and estimate [pic]

b. take two more samples and find the average of their [pic]

c. let [pic]= .50

d. let [pic]= .95

ANSWER: c

26. Which of the following statements is true for the following data values: 7, 5, 6, 4, 7, 8, 12?

a. The mean, median and mode are all equal

b. Only the mean and median are equal

c. Only the mean and mode are equal

d. Only the median and mode are equal

ANSWER: a

28. In testing the hypothesis

[pic]75

[pic][pic] < 75

if the value of the test statistic equals –2.42, then the p-value is:

a. .5078

b. 2.420

c. .9922

d. .0078

ANSWER: d

29. As the degrees of freedom for a t distribution increase, the [pic] value for a given tail area:

a. increases

b. approaches 1.0

c. approaches the [pic] value

d. approaches 0.

ANSWER: c

30. In testing the hypotheses

[pic]

[pic]

at the 5% significance level, if the sample proportion is .45, and the standard error of the sample proportion is .035, the appropriate conclusion would be:

a. to reject [pic]

b. not to reject [pic]

c. to reject [pic]

d. to reject both [pic] and [pic]

ANSWER: b

31. If some natural relationship exists between each pair of observations that provides a logical reason to compare the first observation of sample 1 with the first observation of sample 2, the second observation of sample 1 with the second observation of sample 2, and so on, the samples are referred to as:

a. matched samples

b. independent samples

c. weighted samples

d. random samples

ANSWER: a

32. In a given hypothesis test, the null hypothesis can be rejected at the .10 and .05 level of significance, but cannot be rejected at the .01 level. The most accurate statement about the p-value for this test is:

a. p-value = .01

b. p-value = .10

c. .01 < p-value < .05

d. .05 < p-value < .10

ANSWER: c

33. A professor of statistics refutes the claim that the average student spends 3 hours studying for the midterm exam. Which hypothesis is used to test the claim?

a. [pic]3

[pic]

b. [pic]

[pic][pic]

c. [pic]3

[pic]

d. [pic]

[pic]

ANSWER: b

35. A confidence interval is defined as:

a. a point estimate plus or minus a specific level of confidence

b. a lower and upper confidence limit associated with a specific level of confidence

c. an interval that has a 95% probability of containing the population parameter

d. a lower and upper confidence limit that has a 95% probability of containing the population parameter

ANSWER: b

37. Based on sample data, the 90% confidence interval limits for the population mean are

LCL = 170.86 UCL = 195.42.

If the 10% level of significance were used in testing the hypotheses

[pic]

[pic],

the null hypothesis:

a. would be rejected

b. would not be rejected

c. would have to be revised

d. None of the above

ANSWER: a

39. Which of the following statements about the arithmetic mean is not always correct?

a. The sum of the deviations from the mean is zero

b. Half of the observations are on either side of the mean

c. The mean is a measure of the middle (center) of a distribution

d. The value of the mean times the number of observations equals the sum of all of the observations

ANSWER: b

40. In a hypothesis test for the population variance, the hypotheses are

[pic]

[pic].

If the sample size is 20 and the test is being carried out at the 5% level of significance, the null hypothesis will be rejected if:

a. [pic]

b. [pic]

c. [pic]

d. [pic]

ANSWER: c

41. Which of the following is not a part of the formula for constructing a confidence interval estimate of the population mean?

a. A point estimate of the population mean

b. The standard error of the sampling distribution of the sample mean

c. The confidence level

d. The value of the population mean

ANSWER: d

42. The lower limit of a confidence interval at the 95% level of confidence for the population proportion if a sample of size 200 had 40 successes is:

a. .2554

b. .1446

c. .2465

d. .1535

ANSWER: b

44. In constructing a 90% interval estimate for the ratio of two population variances, [pic]/[pic], two independent samples of sizes 40 and 60 are drawn from the populations. If the sample variances are 515 and 920, then the lower confidence limit is:

a. .352

b. .341

c. .890

d. .918

ANSWER: a

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download