You Are Given the Following Information Obtained from a Random
You are given the following information obtained from a random sample of 4 observations from a large, normally distributed population.
a.What is the point estimate of ?
b.Construct a 95% confidence interval for .
c.Construct a 90% confidence interval for .
d.Discuss why the 90% and 95% confidence intervals are different.
The monthly incomes from a random sample of faculty at a university are shown below.
Compute a 90% confidence interval for the mean of the population. The population of all faculty incomes is known to be normally distributed. Give your answer in dollars.
Fifty students are enrolled in an Economics class. After the first examination, a random sample of 5 papers was selected. The grades were 60, 75, 80, 70, and 90.
a.Calculate the estimate of the standard error of the mean.
b.What assumption must be made before we can determine an interval for the mean grade of all the students in the class? Explain why.
c.Assume the assumption of Part b is met. Provide a 90% confidence interval for the mean grade of all the students in the class.
d.If there were 200 students in the class, what would be the 90% confidence interval for the mean grade of all the students in the class?
A local university administers a comprehensive examination to the recipients of a B.S. degree in Business Administration. A sample of 5 examinations is selected at random and scored. The scores are shown below.
Use Excel to determine an interval estimate for the mean of the population at a 98% confidence level. Interpret your results.