Use the sample information x

= 37, = 5, n = 15 to calculate the following confidence intervals for assuming the sample is from a normal population.

(a) 90 percent confidence. (Round your answers to 4 decimal places.)

The 90% confidence interval is from to

(b) 95 percent confidence. (Round your answers to 4 decimal places.)

The 95% confidence interval is from to

(c) 99 percent confidence. (Round your answers to 4 decimal places.)

The 99% confidence interval is from to

(d) Describe how the intervals change as you increase the confidence level.

multiple choice

• The interval gets narrower as the confidence level increases.
• The interval gets wider as the confidence level decreases.
• The interval gets wider as the confidence level increases.
• The interval stays the same as the confidence level increases.