NOTE: QUESTIONS Q. #1-#4 REFER TO THE FOLLOWING LEAST SQUARES REGRESSION EQUATION:

Y' = .005(X) + .40

FOR PREDICTING COLLEGE GPA FROM SAT I VERBAL SCORES.

1. The coefficient of X (.005) indicates that the correlation between college GPAs and SAT I scores is

a) weak.

b) strong.

c) negative.

d) positive.

2. If a student scores 600 on the SAT I, the predicted GPA for this student would be

a) 0.70

b) 3.00

c) 3.40

d) 4.00

3. A student concentrates on raising his SAT I score in order to also raise his college GPA. This strategy is questionable because it assumes that the relationship between SAT I scores and college GPAs is

a) reliable

b) strong

c) positive

d) cause-effect

4. A predicted college GPA is unlikely to coincide with a student's true GPA because the relationship between SAT I score and college GPAs is

a) weak.

b) imperfect.

c) negative.

d) curvilinear.

5. When testing a hypothesis, rejection regions are located in the

a) extreme areas of the hypothesized sampling distribution.

b) middle areas of the hypothesized sampling distribution.

c) most sensitive areas of the hypothesized sampling distribution.

d) most questionable areas of the hypothesized sampling distribution.

6. In a z test, the z ratio indicates how many __________units the sample mean deviates HEA 600 Page 2 of 6 from the hypothesized population mean.

a) original

b) standard deviation

c) standard error

d) critical

7. Critical z scores separate

a) true and false hypotheses.

b) valid and invalid samples.

c) common and rare outcomes.

d) correct and incorrect decisions.

8. The level of significance indicates the

a) proportion of probable outcomes.

b) importance of the statistical analysis.

c) probability that a correct decision has been made.

d) degree of rarity required to reject the null hypothesis.

9. Given critical z values of 1.96 and an observed z value of -2.40, the appropriate decision is to

a) retain the null hypothesis.

b) reject the null hypothesis.

c) neither retain nor reject, but increase the size of the sample.

d) neither retain nor reject, but conduct another investigation.

10.Increasing the size of the sample is

a) guarantees that the sample will be representative of the population

b) reduces the variability of the sampling distribution

c. changes the variability of the population

d. produces all of the above effects

11.An investigator is concerned only about detecting the possibility that the mean IQ for a population of high school students is greater than 100. Therefore, the alternative hypothesis should take the form:

a. = 100

b. 100

c. < 100

d. > 100

12.If the null hypothesis false and reject this null hypothesis, we have made a

a. correct decision

b. mistake

c. type I error

d. type II error

13.The larger the sample size,

a) the smaller the standard error and the narrower the confidence interval

b) the smaller the standard error and the wider the confidence interval

c) the larger the standard error and the narrower the confidence interval

d) the larger the standard error and the wider the confidence interval

14.When sample size is sufficiently large, about _____ percent of all sample means are within one standard error of the sampling distribution mean. HEA 600 Page 3 of 6

a. 34

b. 50

c. 68

d. 95

15.The largest level of significance reported in most journals equals

a. .10

b. .05

c. .01

d. .001

16.The null hypothesis

a) supports the alternative hypothesis.

b) contradicts the research hypothesis.

c) reflects the true state of affairs.

d) reflects the truth most of the time.

17.Each t distribution is associated with a special number that most directly reflects the

a. degrees of freedom

b. sample size

c. sample standard deviation

d. null hypothesized value

18.You might choose to survey an entire population if the population is

a) small

b. accessible

c. real

d. important

19.On the assumption that voters have no preference for either of four candidates, the probability of a vote for one of these candidates, say candidate A, equals

a. 1/2

b. 1/3

c. 1/4

d. none of the above

20. As used in the definition of a sampling distribution, all possible samples refers to

a) the number of samples required to completely survey a population.

b) an infinitely large number of samples.

c) a very large number of samples.

d) the number of different ways that a sample can be selected from a population.

21. The central limit theorem concentrates on changes in the ________________ of a sampling distribution.

a. size

b. shape

c. central tendency

d. variability

22. Before generalizing beyond the existing data, we must always measure the effect of

a. chance

b. the independent variable

c. the investigator

d. the generalization.

23. In a study with 30 grade-school children per group, students in the experimental reading program do 10 points better, on the average, than do students in the regular program. Therefore you can conclude that this difference is

a. statistically significant.

b. important.

c. statistically significant and important.

d. undecipherable without additional information.

24. Published reports often include parenthetical statements that summarize HEA 600 Page 4 of 6

a. the research hypothesis.

b. any assumptions associated with the statistical analysis.

c. the statistical analysis.

d. the statistical analysis, including a p-value.

25. The less structured (p-value) approach to hypothesis testing is very attractive when

a. test results are borderline.

b. a type I error is particularly serious.

c. sample size is small.

d. the null hypothesis is false because of a large effect.

26. Two-tailed p-values can be described as being

a. twice as large as the corresponding one-tailed p-value.

b. appropriate when the investigator is concerned about deviations in either direction.

c. equivalent shaded areas located in both tails of the sampling distribution.

d. all of the above

(Q. # 27 though 30)

A pollster reports, with 95 percent confidence, that between 55 and 61 percent of all Americans favor mandatory drug testing for employees in positions of public trust (bus drivers, airline pilots, etc).

27. The margin of error in this survey equals

a) 3 percent.

b) 6 percent.

c) 55 percent.

d) some unknown percent.

28. The point estimate for the unknown population proportion (who favor mandatory drug testing) equals

a) 55 percent.

b) 58 percent.

c) 61 percent.

d) some unknown percent

29. The boundaries of this confidence interval (55 to 61 percent) suggest that

a) a majority of Americans probably favor mandatory drug testing.

b) a majority of Americans definitely favor mandatory drug testing.

c) it is impossible to know whether a majority of Americans favor mandatory drug testing.

d) all of the above are true, depending on your perspective.

30. When estimating the population standard deviation, always use the version of the sample standard deviation where

a) n appears in the denominator.

b) n - 1 appears in the denominator.

c) raw scores can be used.

d) the sample mean needn't be calculated

31.Which of the following is true about Type II errors?

a) the probability of one occurring is equal to the alpha level

b) they cannot occur if the statistical test is powerful enough HEA 600 Page 5 of 6

c) they occur when a true effect exists, but we fail to discover it in our study

d) they occur when we reject the null hypothesis, when we really should not do so

32.A set of data has a mean of 12 and a 95% confidence interval of 10-14. What does this mean?

a) the standard deviation will be 14-10, or 4

b) you can be 95% sure that 12 is the population mean

c) in order for the mean to be significantly different fro some other mean, the scores producing the other mean cannot be between 10 and 14

d) you can be quite sure that the population mean falls somewhere between 10 and 14

33. Given a concern only that meditation improves college grade point averages, the alternative hypothesis should translate into a

a) two-tailed test.

b) one-tailed test with the upper tail critical.

c) one-tailed test with the lower tail critical.

d) test with the .05 level of significance.