The number of violent crimes committed in a day possesses a distribution with a mean of 4.2 crimes per day and a standard deviation of 6 crimes per day. a random sample of 100 days was observed, and the mean number of crimes for the sample was calculated. describe the sampling ditribution of the sample mean.

a. approximately normal with mean=4.2 and standard deviation =0.6

b. approximately normal with mean = 4.2 and standard deviation =6

c. shape unknown with mean= 4.2 and standard deviation =6

d. shape unknown with mean= 4.2 and standard deviation =0.6

Two researchers are attempting to create a new psychotherapy protocol that more reduces panic attacks. they believe that they have succeeded and are now in the clinical trial period of their protocol's development. they are working with several cohort groups, some of which have been through the new protocol, while others have done the standard protocol currently recommended. if these researchers are interested in evaluating the difference in the percentage of test subjects who successfully decreased their panic attacks in 2 months on the new protocol versus the percentage of test subjects who successfully decreased their panic attacks in 2 months with the traditional protocol, which of the following statistical tests would be most appropriate? a. analysis of variance (anova) b. correlation c. chi-square test d. paired t-test e. independent t-test