Use the sample information xx = 41, = 4, n = 20 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.)

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

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

(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.