UOM Dartmouth Confidence Interval for The Population Questions

Use the Student’s t distribution (using tables from textbook not online resource and round your answer to three decimal places as provided in textbook tables.)

Find t_c for a 0.95 confidence level when the sample is 18.

Find t_c for a 0.99 confidence level when the sample is 7.

Find t_{c for a 0.90 confidence level when the sample is 8}.

Find t_c for a 0.95 confidence level when the sample is 5.

Do you want to own your own candy store? Wow! With some interest in running your own business and a decent credit rating, you can probably get a bank loan on startup costs for franchises such as Candy Express, The Fudge Company, Karmel Corn, and Rocky Mountain Chocolate Factory. Startup costs (in thousands of dollars) for a random sample of candy stores are given below. Assume that the population of x values has an approximately normal distribution.

Using the sample data the following measurements were verified with a calculator:

• sample mean startup cost x = $107.1 thousand and
• sample standard deviation s = $30.7 thousand

Find a 90% confidence interval for the population average startup costs μ for candy store franchises. (Round your answers to two decimal places.)

FOR THIS CONFIDENCE INTERVAL:

1. What is the symbol for the point estimate? $

2. What is the value of the point estimate? $ thousand

3. What distribution will be used?(standard normal z or student’s t)?

4. What is the critical value?

5. What is the standard error of the sampling distribution? $ thousand

6. What is the maximal margin of error (E)? $ thousand

7. State the confidence interval indicating the population parameter:

$thousands < < $thousands)