Question

a.) A study of class attendance and grades among first-year students at a state university showed that in general students who attended a higher percent of their classes earned higher grades. Class attendance explained r2 = 64% of the variation in grade index among the students. What is the numerical value of the correlation between percent of classes attended and grade index? (Use 2 decimal places.)

b.) An opinion pollster asks 100 college seniors how they view their job prospects. In all, 53 say "Good." The large-sample 96% confidence interval for estimating the proportion of all college seniors who think their job prospects are good is which of the following?

-0.530 ± 0.070

-0.530 ± 0.087    

-0.530 ± 0.103

c.) A study of commuting times reports the travel times to work of a random sample of 977 employed adults in Chicago. The mean is x = 53.0 minutes and the standard deviation is s = 48.9 minutes. What is the standard error of the mean? (Round your answer to four decimal places.)

Answer 1