In a random sample of 20 people, the mean commute time to work was 32.5 minutes and the standard deviation was 7.1 minutes. Assume the population is normally distributed and use a t-distribution to construct a 95% confidence interval for the population mean What is the margin of error of u? Interpret the results. The confidence interval for the population mean is (Round to one decimal place as needed.)

Suppose that textbook weights are normally distributed. You measure 33 textbooks' weights, and find they have a mean weight of 61 ounces. Assume the population standard deviation is 13.2 ounces. Based on this, construct a 90% confidence interval for the true population mean textbook weight. Round answers to 2 decimal places.

A sample of 20 bags of mulch had a mean weight of 52 pounds with a standard deviation of 3.8 pounds. Find the 95% confidence interval of the true mean. Show all your work for or explain how you obtained your answer in the space provided below.

The distribution of study times for first-year students follow a Normal distribution with a standard deviation σ = 48 minutes. Suppose a sample of 344 students found that the mean study time for these students was x¯= 170 minutes per week. Use this to find a 94.38% confidence interval to estimate the mean study time for all students. We are 94.38% confident that the mean study time for first-year students is between the following ( answer) minutes and  ( answer) minutes. The answer needs to be the mean study time for first-year students is between what amount of minutes and the following minutes.