Question

9. Let c = 0.98 and n = 22. Find the critical value, tc.

10. Let c=0.80, s=5, and n=14.Find the margin of error, E.

11. Use the information below to to construct a confidence interval for the population mean, μ. Round your results to 3 decimal places for this problem. Assume that the population is nor- mally distributed. Let c = 0.90, x = 48.51, s = 2.15, and n = 19.

Answer 1

(9) Given: c=0.98, n=22

We first need to find the , i.e.,

Critical value:

(10) Margin of error(E) is given as:

Given:

So, the margin of error(E) is calculated as

(11) 90% confidence interval for the population mean

Given:

Confidence interval is calculated using the using the formula-   

So, the 90% confidence interval for the population mean is . We are 90% confident that this confidence interval contains the true population mean, i.e.,