® ह Osh 1 मर्ड +7

A researcher is interested in whether participat-ing in sports positively influences self-esteem in young girls. She identifies a group of girls who have not played sports before but are now plan-ning to begin participating in organized sports. The researcher gives them a 50-item self-esteem inventory before they begin playing sports and administers the same test again after 6 months of playing sports. The self-esteem inventory is measured on an interval scale, with higher num-bers indicating higher self-esteem. In addition, scores on the inventory are normally distributed. The scores follow: Before: 44 40 39 46 42 43 After: 46 41 41 47 43 45 a. What statistical test should be used to analyze these data? b. Identify H0 and Ha for this study. c. Conduct the appropriate analysis. d. Should H0 be rejected? What should the researcher conclude? e. If significant, compute and interpret the effect size.

(a) What does the Central Limit Theorem say, in plain language? (b) What do we use the CLT for, in this class? (c) Why do we need condence intervals? Isn't a sample mean good enough by itself?

In 1940 the average size of a U.S. farm was 174 acres. Let’s say that the standard deviation was 57 acres. Suppose we randomly survey 37 farmers from 1940.   A) Give the distribution x̅  (round your standard deviation to two decimal places.) x̅~______(______,______)   B) The middle 50% of the distribution for x̅ the bounds of which from the distance represented by the IQR, lies between what two values? (round your answer to two decimal places.) ______acres (smaller value) ______ acres (larger value)