Suppose that Amazon has begun to test the use of drones for same-day delivery. If you wished to test: H subscript O colon space sigma squared less or equal than 0.75 H subscript A colon space sigma squared greater than 0.75 and n = 20 home deliveries were included in the dataset, with a sample variance of 0.82, calculate the value of the Test Statistic (TS) that you would use to perform this test. Round off your answer to the third decimal place: The TS, rounded off as instructed, is:

A phone service provider hypothesizes that Android users have a lower credit score rating than iPhone users and, if true, would like to build a marketing campaign around that idea. In order to test their hypothesis, they collect the data in the table below. Assume that credit scores are approximately normally distributed and that the variance in scores is the same between the two groups. What is the p- value of the test? Round your answer to three decimal places. Android Users Credit Scores 415 565 544 617 675 381 552 673 623 691 iPhone Users Credit Scores 631 659 549 681 632 596 695 673 685 653 535 593 710

Given below are the analysis of variance (ANOVA) results from a Minitab display. Assume that you want to use a 0.01 significance level in testing the null hypothesis that the samples come from populations with the same mean. Source    DF     SS            MS         F        P-val Factor     2.      2280.0    1140.0    7.9     5.39E–04 Error      144    20691.7   143.7 Total      146    22971.8 What can you conclude about the equality of the population means? (circle one) Reject H0 since the p-value is greater than the significance level.  Fail to reject H0 since the p-value is greater than the significance level.  Reject H0 since the p-value is less than the significance level. Fail to reject H0 since the p-value is less than the significance level.

You work for a soft-drink company in the quality control division. You are interested in the variance of one of your production lines as a measure of consistency. The product is intended to have a mean of 12 ounces, and your team would like the variance to be as low as possible. You gather a random sample of 16 containers. Estimate the population variance at a 80% level of confidence. 11.82 11.83 11.85 11.89 11.9 11.97 12 12 12 12.01 12.02 12.04 12.05 12.11 12.16 12.18 Variance of Data: 0.012 Note: Round all values to 3 decimals and use those rounded values in subsequent calculations. a) Find the lower and upper x critical values at 80% confidence: Lower: Upper: b) Report your confidence interval for o?: Lower Bound: Upper Bound: