1-A researcher wants you to evaluate whether the severity of anxiety has increased recently among healthy adults. Based on U.S. Census Bureau Household Pulse Survey (HPS) data, the CDC reported the average level of anxiety was = 2.0 in 2020. The researcher collected a sample of 800 participants and found an average anxiety level of M = 2.3, SD = 3.

Report the t for a one sample t-test (round to the nearest two decimal places).

2-A therapist collects data from her clients about their current level of life satisfaction during their first therapy session. Then, she surveys them again during their last session to test whether their life satisfaction improved. She finds on average that her clients' level of life satisfaction increases by 1.20 points, and the data on the difference between their first and last session has a variance of 16.

Report the effect size using Cohen's d (report as a numerical value).

3-A researcher compares pre-school students who attend in the morning (n = 6) to those who attend in the afternoon (n = 6) and assigns their art projects creativity scores (Mmorning = 5 and Mafternoon = 10). The researcher has calculated the pooled variance = 12.

Report the t for an independent samples t-test:

Report the effect size using Cohen's d:

Round all answers to the nearest two decimal places.

4-Which of the following statements is true about pooled variance?

It acts like a weighted average of two variances.

It is the sum of the two variances.

It finds the ratio of the larger to smaller variance.

It is the difference of the two variances.