Use the sample information x-bar = 2.4, = 0.15, n = 9 to calculate the following

Question:

Use the sample information x-bar = 2.4, σ = 0.15, n = 9 to calculate the following confidence intervals for assuming the sample is from a normal population:
(a) 90 percent confidence;
(b) 95 percent confidence;
(c) 99 percent confidence.
(d) Describe how the intervals change as you increase the confidence level.