Question 1

Which of the following are parametric statistical tests that may be used to measure, clarify, or evaluate causation?

Accepted Answer

Parametric tests assume underlying statistical distributions in the data. The t-test for independent samples (A) and dependent samples (C), ANOVA (E), and Tukey HSD test (F) are parametric tests used to evaluate differences between group means, which can help in assessing causation. The Mann-Whitney U test (B), Wilcoxon signed-rank test (D), Kruskal-Wallis test (G), and Chi-square test (H) are non-parametric tests.

Question 2

What does the two-way chi-square test measure?

Accepted Answer

The two-way chi-square test measures whether there is an association between two categorical variables, essentially testing if one variable seems related to another one. It does not measure causation, intervention effects, or changes over time.

Question 3

A statistician measures the difference in songbird warble variation in 25 mockingbirds, both before and after nutritional supplementation with Dr. Petit Oiseau's Musical Bird Seed. Warble variation is determined by a cranky librarian, who characterizes the birds, before and after treatment, as one of the following "Lots of Notes There!" "Fair Variety," and "Quite the Redundant Little Song." What considerations determine choice of a test for this research?

Accepted Answer

B, C, D, F

Question 4

A statistician measures the difference in songbird warble variation in 25 mockingbirds, both before and after nutritional supplementation with Dr. Petit Oiseau's Musical Bird Seed. Warble variation is determined by a computer program that detects sound frequency and pattern changes during a 15-minute period twice a day, and these data are averaged to represent number of warble variations per minute. What considerations determine choice of a test for this research?

Accepted Answer

The answer of A statistician measures the difference in songbird...

Question 5

What are the principal reasons why a nonparametric test of causality is used instead of a parametric one?

Accepted Answer

Nonparametric tests are used when the assumptions for parametric analyses, such as normal distribution of data, are not met (A, C), or when the data are measured at a less than interval level, such as ordinal data (D).

Question 6

In an ANOVA calculation evaluating causation, the mean square within groups value represents the ordinary amount of variation that exists in the data set. What does the mean square between groups value represent?

Accepted Answer

The mean square between groups value represents the effect produced by the interventional conditions, indicating how much the group means differ due to the treatment or intervention.

Question 7

Below the third table in a research report, concerning switching infants to cow's milk at 6 months of age instead of 12 months, is a notation: "t(22) = -0.76, p = .41" What does this mean?

Accepted Answer

The answer of Below the third table in a research...

Question 8

Which test is essentially a comparison of means?

Accepted Answer

The t-test is specifically designed for comparing means between groups, making it the correct choice for a test that essentially compares means.

Question 9

What do the t-test and the ANOVA have in common?

Accepted Answer

Both t-tests and ANOVAs assume a normal distribution of the dependent variable, compare groups to determine if there are significant differences, can be used with interval-level dependent variables, and are considered parametric analyses, meaning they assume certain parameters about the data distribution.

Question 10

What is unique about chi-square analysis?

Accepted Answer

Chi-square analysis is unique because it is used for two nominal variables, allowing researchers to examine the relationship between two categorical variables. Unlike parametric tests, it does not require the assumption of normal distribution.

Question 11

A researcher is conducting a study to discover whether the provision of hypnosis with dental work affects pain. The researcher's three groups are (1) hypnosis before and during the procedure, (2) hypnosis before but not during the procedure, and (3) no hypnosis. If the researcher plans to use an ANOVA for the statistical analysis, which would be an acceptable way to measure pain, for this study?

Accepted Answer

The answer of A researcher is conducting a study to...

Question 12

Which of the following results would represent statistical significance, if the level of significance were set at 0.05 for each?

Accepted Answer

A) t = 8.43, p < 0.01 is statistically significant because the p-value is less than the level of significance (0.05).E) r_s = 0.74, p = 0.049 is statistically significant because the p-value is less than the level of significance (0.05).

Question 13

Why is post hoc statistical testing not performed with a two-group ANOVA?

Accepted Answer

In a two-group ANOVA, if the hypothesis testing reveals a significant difference, it is clear that the difference is between the two groups being compared. Post hoc tests are designed to identify which groups differ from each other when there are more than two groups involved.

Question 14

A researcher designs a study to measure whether receiving a free season pass to a beautiful ski resort near Bountiful, Utah, increases the number of days a subject who has lived in the area for 1 to 3 years skis during the season. An independent samples t-test of correlation is used to measure the effect of receiving a season pass upon number of ski days. If, instead, the researcher decided to measure the subjects' responses by asking them to check one of these four replies on a survey, "Much more often than last year," "More often than last year," "Just about the same as last year," or "Less often than last year," why would the independent samples t-test have to be abandoned for a Mann-Whitney U test instead?

Accepted Answer

The answer of A researcher designs a study to measure...

Quiz 25: Using Statistics to Determine Differences