Assume a random sample of n = 5 measurements from a normal distribution. Compare the standard normal z-values with the corresponding t-values if you were forming a 99% confidence interval.     2.576; 4.604 1.282; 1.533  1.96; 2.776 1.645; 2.132

A sample of the length in inches for newborns is given below. Assume that lengths are normally distributed. Find the 99% confidence interval of the mean length.   Length 15.2 15.6 20.6 16.3 15.4 17.4 18.1 20.6 18.6 20.7

Tina catches a 14-pound bass.  She does not know the population mean or standard deviation.  So she takes a sample of five friends and they say the last bass they caught was 9, 12, 13, 10, and 10 pounds.  Find the t and calculate a 95% (α = .05) confidence interval.

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.

Assume that a sample is used to estimate a population mean u. Use the given confidence level and sample data to find the margin of error. Assume that the sample is a simple random sample and the population has a normal distribution.  95% confidence; n=12; x=46.1; s=5.7

A professor wants to estimate how many hours per week her students study. A simple random sample of 72 students had a mean of 19 hours of studying per week. Construct a 90% confidence interval for the mean number of hours a student studies per week. Assume that the population standard deviation is known to be 2.1 hours per week. Round to two decimal places.

Use the standard normal distribution or the t-distribution to construct a 90% confidence interval for the population mean. Justify your decision. If neither distribution can be used, explain why. Interpret the results. In a random sample of 46 people, the mean body mass index (BMI) was 27.8 and the standard deviation was 6.09. Which distribution should be used to construct the confidence interval? Choose the correct answer below. ○ A. Use a t-distribution because the sample is random, the population is normal, and σ is unknown. ○ B. Use a normal distribution because the sample is random, the population is normal, and σ is known. ○ C. Use a t-distribution because the sample is random, n ≥30, and σ is unknown. ○ D. Use a normal distribution because the sample is random, n ≥30, and σ is known. ○ E. Neither a normal distribution nor a t-distribution can be used because either the sample is not random, or n <30, and the population is not known to be normal.