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Consider a study in which the population variance estimate based on an experimental group of 10 participants is 70, and the population variance estimate based on a control group of 20 participants is 50. Show your work and Compute the pooled estimate of population variance.

For each of the following studies, indicate whether you would use a t test for a single sample, t test for dependent means, or a t test for independent means. (a) A school counselor randomly assigns a group of 50 high school students to receive a new assertiveness training program and 45 other high school students to receive the standard after-school program that focuses on social skills. The counselor later measures how well each group performs on a measure of interpersonal assertiveness. (b) A psychologist measures 100 patients in terms of their anxiety levels before and after undergoing a newly developed treatment. (c) The coach of a college football team conducts an informal survey showing that members of the team study an average of 3.5 hours per day. The coach makes the claim that this is equivalent to the amount of time students at the college study in general. An instructor believes that the coach is incorrect and randomly selects 50 students from the college and asks them how much they study each day. These 50 students report studying an average of 5.2 hours per day. (d) A school psychologist tests the memory scores of each of a group of 15 students twice, once while in a very noisy room and once while in a quiet room and then compares the scores. (e) A student counselor measures the intelligence of college students (n = 25) who are first born in their families compared to those who were born last in their families (n = 40).

Relational Listening is the active and involved listening we do with people we love and care about. This is listening where we:

Chapter 10

Based on the following results, which would be the correct use of the formula t = (M 1–M 2) /S Difference? Sample 1: Mean = 60; Variance of the distribution of means = 2. Sample 2: Mean = 50; Variance of the distribution of means = 7.

In an ANOVA, if the between-group variance estimate is 640 and the within-group variance estimate is 110, the F ratio is __________.

Suppose a study has a sample mean of 95, the mean of Population 2 is 75, and the standard deviation of the distribution of means is 5. Using a single-sample t test, what is the t score?

A sociologist interested in salesperson-consumer interaction wanted to know if customers really are influenced to buy more from sales clerks who smile. To test this, clerks at eight stores in a large Canadian clothing chain were given special instructions at the start of a week, and the number of sales over the week were recorded. Four of the stores were randomly selected to have the clerks receive instructions to be especially courteous and to smile a lot. Clerks at four other stores were simply instructed to be especially courteous. Sales (in thousands of dollars) for the four stores in the smile condition were 36, 40, 36, and 44; sales for the four stores in the control condition were 40, 31, 27, and 30. Do these results suggest that customers might buy more if they encounter smiling sales clerks? (Use the .05 level.) a. Use the five steps of hypothesis testing and show your calculations.b. Explain your findings.

A sports psychologist gave a standard written test of eating habits to 12 randomly selected professionals, four each from baseball, football, and basketball. The results were as follows:Is there a difference in eating habits among professionals in the three sports? (Use the .05 significance level.)a. Use the five steps of hypothesis testing, showing your calculations.b. Sketch the distribution involvedc. Explain results

The number of degrees of freedom used to determine the cut-off sample score from a t table when conducting a t test for independent means is the