Quiz (Chapter 17) Inferences on Percentages, Proportions, and Frequencies Introduction If concerned with group membership, researchers compute summaries such as frequencies, _____, or _____. What level of measurement is contained in the data if a researcher measures people in terms of gender? The Sign Test, the Binomial Test, and Fisher's Exact Test Look at Excerpt 17.1. If 15 (rather than 12) of the 20 people had correctly discriminated the difference in circles, the p-value would have been _____ (larger/smaller) than 0.2517. Can a sign test be used with 1 group measured twice? With 2 matched groups? With 2 independent groups? The binomial test is exactly like a sign test, except the _____ (former/latter) has a more "flexible" Ho. Answer the 3 parts of Question 4, but this time think of the binomial test rather than the sign test. How many comparison groups are involved in a Fisher's Exact Test? Must these groups be matched? The null hypothesis in a Fisher's Exact Test says that the population proportions are ____ (equal/equal to .50). In Excerpt 17.4, the sample data would have been most "in line with" the null hypothesis if ___ of the 32 control group individuals had said that they were very satisfied with the overall treatment and outcome. Chi-Square Tests: An Introduction (T/F) Most chi-square tests (but not all of them) deal with nominal data. What Greek symbol is used to indicate that a chi-square tests has been conducted? (T/F) If a chi-square test is used with frequencies, it most likely is Pearson's approximation to chi square. Three Main Types of Chi-Square Tests (T/F) A 4-category 1-sample c2 test could yield a "p<.05" result if 25% of the sample falls in each category. If 30 men in the male sample exercise but 10 don't, how many of the 60 women in the female sample would have to exercise in order for the sample data to be in full agreement with the chi-square null hypothesis? In Excerpt 17.9, how many df were associated with the chi square test that was conducted? (T/F) When chi square is used with a contingency table, the researcher must specify the values of P in Ho. If, in Table 17.3 (on page 416), the control group's percentages for "Technique" and "Don't Know" had been reversed, the computed value of c2 in Excerpt 17.10 would have been ______ (smaller/larger) than 21.80. (T/F) In a "cross-tabulation analysis," the data are means and standard deviations. Chi Square as a Correlational Probe When chi-square is used in a correlational sense, researchers sometimes call it a "chi square test of ____." For 2x2 contingency tables, chi-square can be converted into a correlational index called ____. For contingency tables with 3 or more rows/columns, c2 can be converted into what correlational index? In Excerpt 17.14, if the 2 Black percentages had been 50% and 50%, the numerical value of c2 would have been ______ (larger/smaller) than 9.94, and the numerical value of phi would have been ______ (larger/smaller) than .28. Issues Related to Chi-Square Tests With chi-square tests, the df are determined by ____. (a) the sample size (b) the number of categories If a researcher used chi-square to see if a relationship exists between the political affiliation of bumper stickers (Republican vs. Democrat) and driver's age (<30, 30-50, >50), the df would be equal to __. If a chi-square test comparing the % of men and women getting one or more traffic tickets in the past year leads to a significant result, a post hoc test ____ (would/would not) be needed to clarify the results. Chi-square should not be used if the _____ (expected/observed) frequencies are too small. Researchers sometimes use the "Yates correction" when their chi square's df is ___ (1/more than 1). McNemar's Chi Square McNemar's chi square is appropriate when the 2 samples of data are ______ (independent/correlated). McNemar's chi-square test is very much like a sign test paired t-test two-way ANOVA hierarchical multiple regression McNemar's chi-square test ____ (can/can't) be used with matched groups. The Cochran Q Test Cochran's test is used when there are ___ (2/more than 2) _____ (independent/correlated) samples giving data on a dependent variable having ___ (2/more than 2) categories. If Cochran's test leads to a rejection of the omnibus null hypothesis, what test will probably be used to make pairwise post hoc comparisons? The Use of z-Tests When Dealing With Proportions Researchers sometimes use z-tests rather than sign, binomial, and McNemar tests when: underlying assumptions are not met the null hypothesis can't be rejected the sample sizes are big A Few Final Thoughts (T/F) Statistical tests that focus on frequencies, percentages, or proportions have a built-in feature that prevents Type I errors from occurring. The Bonferroni technique ___ (can/can't) be used with tests on frequencies, percentages, and proportions. To judge whether a chi-square-based effect is small, medium, or large, researchers often convert their chi-square calculated value into a ___ or ___ correlation. In Excerpt 17.25, the researchers conducted a(n) _______ (a priori/post hoc) power analysis. Click here for answers.