Question

1. An overnight delivery service has a promotional discount rate in effect this week only. Twelve packages mailed this week were randomly selected to see if there is evidence that the mean weight of packages sent this week is higher than usual. A 95% confidence interval for µ was found to be . Using the context of the problem, give an interpretation of the interval
2. In a survey about fears, 45 out of 250 randomly selected adults said that they were afraid of the dentist’s chair. Based on this sample data, a 95% confidence interval for the population proportion was found to be . Using the context of the problem, give an interpretation of the confidence interval.

Answer 1

Interpretation of the confidence interval is as follows. 1) We are 95% confident to conclude that the true population mean weight of packages sent this week is lies between the interval (10.64,13.08) 2) We are 95% Confident to conclude that the true population proportion of adults who said that they are afraid of the dentists chair is lies between the interval (0.136,0.228)