Length of pregnancy in weeks follows a normal distribution. Use the random sample data below to construct the "margin of error" for a confidence interval with a 90% level of confidence for the length of pregnancy in weeks. x- 281 days S = 15 days n=52 None of these 3.6 days 3.1 days 2.7 days 3.5 days

Daily Driving The average number of miles a person drives per day is 24. A researcher wishes to see if people over age 60 drive less than 24 miles per day. She selects a random sample of 25 drivers over the age of 60 and finds that the mean number of miles driven is 23.4. The population standard deviation is 4.1 miles. At a = 0.01, is there sufficient evidence that those drivers over 60 years old drive less than 24 miles per day on average? Assume that the variable is normally distributed. Use the critical value method with tables. Part 1 of 5 State the hypotheses and identify the claim with the correct hypothesis. H: u = 24 not claim Η: μ 24 claim The hypothesis test is a one-tailed test. Part: 1/5 Part 2 of 5 Find the critical value(s). Round the answer to at least two decimal places. If there is more than one critical value, separate them with commas. Critical value(s):

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.

Researchers examined the bill color (in hue degree) of male and female zebra finches. Here are the summary statistics from the study. Sex N Mean Standard deviation Males 59 2.91 1.46 Females 60 7.42 2.48 How different are male and female zebra finches in bill color? The margin of error for a 95% confidence interval for the difference in mean bill color μF – μM (in hue degree) is