Quiz Over Chapter 10 of the 6th Edition

Inferences Concerning One or Two Means

Introduction
1. A ____ number of statistical techniques are available to researchers who want to deal inferentially with the mean(s) computed from sample data.
2.  small large
3. The technique of interval estimation can be used in studies where interest lies in one or two means.
4.  True False
Inferences Concerning a Single Mean
1. When a single sample is taken from a population, at what will the researcher be guessing, the sample mean or m?
2.  The sample mean m
3. In general, large sample sizes tend to bring about _____ confidence intervals.
4.  narrow wide
5. In Excerpt 10.4, how much difference was there between the sample mean and the numerical value in the null hypothesis?
6.  0.26 1.09 2.62 3.71 4.999
7. With a single group, the null hypothesis can be rejected when the difference between the sample mean and ____ is larger than would be expected by chance.
8.  the actual population mean the pinpoint number in the null hypothesis
9. If a researcher conducts a t-test on a single group mean, and if df = 19, how many subjects were in the sample?
10.  18 19 20 It's impossible to tell based on the information given
Inferences Concerning Two Means
1. If 2 samples are "correlated," a researcher might refer to them as
2.  paired samples or independent samples. matched samples or unpaired samples. dependent samples or matched samples. Pearson samples or Spearman samples. direct samples or indirect samples
3. If two samples have different ns, this is a "tip-off" that the samples are ____ .
4.  independent correlated
5. If a group's pretest mean is compared against its posttest mean, these two sets of data are considered to be _____ .
6.  independent correlated
7. In comparing 2 means with a statistical test, 2 separate inference are made (one to m1, the other to m2).
8.  True False
9. What could you say about these two statements? (a) Ho: m1 = m2 (b) Ho: m1 - m2 = 0
10.  Neither a nor b is a legitimate null hypothesis. Only a is a legitimate null hypothesis. Only b is a legitimate null hypothesis. Both a and b are legitimate null hypotheses.
11. When comparing 2 means, Ho does not have to be set up in a "no difference" fashion.
12.  True False
13. In Excerpt 10.17, altogether how many men and women were involved in the study?
14.  101 102 104 105 It's impossible to determine.
15. The means of 2 independent samples can be contrasted via a t-test, a __-test, or an __-test.
16.  v; H z; M v; F v; M z; F
17. What do the abbreviations "df" stand for?
18.  Dependence on frequencies Distribution-free Dispersion factor Descriptive fallacy Degrees of freedom
19. In an ANOVA summary table, the calculated value (i.e., F-value) is computed by dividing MSbetween by _____ .
20.  dfbetween dfwithin SSbetween SSwithin MSwithin
21. In an ANOVA summary table, the total number of subjects in both groups = dfbetween + dfwithin + ___.
22.  1 2 3 dftotal MStotal
23. In comparing 2 means via a confidence interval, suppose one end point of the CI is positive while the other end point is negative. This would indicate that there ____ a statistically significant difference between the 2 sample means?
24.  is is not
Multiple Dependent Variables
1. If a researcher has data from 2 groups on 3 dependent variables, and if he/she wants use a t-test to compare the means of the groups, how many t-tests would the researcher perform?
2.  1 2 3 5 6
3. In Excerpt 10.15, the number in parentheses at the end of the final sentence is .008. What would this number have been if there had been 2 rather than 6 virtues?
4.  .004 .016 .025 .05 .10
5. The Bonferroni technique cannot be used when there's only one sample.
6.  True False
7. If the pseudo-Bonferroni technique is used by a ".05" researcher who wants to compare two groups on each of 7 dependent variables, what revised alpha level would he/she probably use?
8.  .35 .07 .05 .01 .007
Effect Size Assessment and Power Analyses
1. When conducting a test on one or two means, do most researchers do something to help them (and their readers) distinguish between statistical and practical significance?
2.  Yes No
3. In Excerpt 10.9, which two numbers should you compare if you're trying to determine whether the difference between the two means has "practical significance"
 6.17 and 2.64 4.48 and 2.35 6.17 and 4.48 2.64 and 2.35
4. Suppose a researcher determines that 20 subjects must be in each sample in order for the statistical comparison of 2 sample means to have a power of .80.  In this study, there will be a 20% chance of a Type __ error.
5.  I II
Underlying Assumptions
1. "Randomness," "independence," and "normality" are three of the 4 underlying ssumptions associated with t-, z-, or F-tests that compare 2 means. What is the 4th underlying assumption?
2.  Equal sample sizes Equal variances Equal p-values Equal critical values
3. If a researcher tests an underlying assumption, he/she hopes to reject the assumption's null hypothesis.
4.  True False
5. In Excerpt 10.15, the results of 3 t-tests are reported. In which of these t-tests do the sample data support most the homogeneity of variance assumption?
6.  The t-test comparing males and females The t-test comparing those 65-74 with those 75 and older The t-test comparing people who visited the 2 different health centres All 3 of the t-tests had equal support for the equal-variance assumption Not enough information is provided in the excerpt to answer the question
7. What makes a statistical comparison of two means robust to the equal variance assumption?
8.  Equal sample sizes Equal sample means Equal sample medians Equal sample modes
1. In Excerpt 10.3, the statistical test showed "no significant difference" (with p = .366). Based on this finding, can the null hypothesis of the z-test be accepted?
2.  Yes No
3. The very small p-value in Excerpt 10.9 strongly suggests that all of the research participants endorsed a smaller number of barriers to exercise at posttest than they did at pretest.
4.  True False
5. The last sentence of Chapter 10 says: "____________ by any of these techniques, regardless of how bold the researchers' claims might be."
6.  Inferences are bound to fail Nothing is proven Valuable insights are provided Findings should be replicated

A Few Tougher Questions Over Chapter 10
1. Whereas a one-tailed test must be used whenever the null hypothesis deals with a single population, a two-tailed test must be used whenever the null hypothesis deals with two populations.
2.  True False
3. In Excerpt 10.11, would the computed F have turned out larger than 8.510 or smaller than 8.510 if the 2 SDs had been smaller (with nothing else about the data being changed)?
4.  Larger Smaller
5. The scores summarized in Excerpt 10.1 most likely were
6.  positively skewed. negatively skewed. not skewed at all.
7. How should the concept of "overlapping distributions" influence how we interpret the assertion in Excerpt 10.8 that "...girls were more accurate on no-go trials during the GNG task ... than boys...."?
8.  Insert "slightly" after the word "were" Insert "significantly" after the word "were" Insert "far" after the word "were" Insert "on average," prior to the word "girls"
9. If, in Excerpt 10.21, alpha had been set equal to .01 (rather than .05), the power analysis would have indicated the need for ___ participants in each group.
10.  more fewer
11. If a one-way analysis of variance is used to compare 2 groups of 20 subjects each, and if the SStotal turns out equal to 86 while the MSerror turns out equal to 2, how large would the calculated value be?
12.  2 4 5 8 10
13. Look at Excerpt 10.23. Which of the following alpha levels would have made Levene's test "conservative" in the sense that this alpha would have made it harder for the researcher to get a desired result from Levene's test?
14.  .01 .15