Your COMM 215 instructor took a random sample of 18 students to examine the number of hours per week students surf the Internet for either personal information or material for course activities. The sample mean response was 6.65 hours and the sample standard deviation was 0.85 hours. Based on these results, and assuming normality for the population distribution of surfing time in hours, the instructor constructed a confidence interval extending from 6.05 to 7.08 hours per week for the population mean. What is the confidence level used for this interval? Type your numerical answer here. Numbers only PART 3 B 1 In a random sample of 21 of 180 employees of a company, the mean number of hours overtime billed in the week of Black Friday was 9.7, with the sample standard deviation of 6.2 hours. Find the upper limit of a 99% confidence interval for the total number of hours overtime billed during the week. Type your numerical answer here. Numbers only Part 3 C 1 Consider 3 national brands of apple pie (A, B, C), and a store brand (D) sold at a local grocery store. Past records show brands A and C were equally preferred, 32% preferred brand B, and 26% preferred the store brand, D. The manager believes that there has been a change in customer preferences and that the preference for store-brand apple pie has increased and perhaps will positively contribute to increased profits. Find the value of the appropriate test statistic for testing the change in customer preferences from the past years. Brand A B C D Number 56 68 28 110 Type your numerical answer here. Numbers only PART 3 D 1 Consider the results for the rate of return for a random sample of 35 mutual funds over the previous 3-year (X) and 5-year (Y) periods. Given the 3-year rate of return of 8.50, what is the upper end point in a 90% prediction interval for the 5-year rate of return? Coefficients | Standard Error Intercept 5.97928 0.34923 0.68594 0.06872 SSxx = 461.700274, MSE = 2.18009 Type your numerical answer here. Numbers only