The standard deviation for a population is σ=14.5. A sample of 25 observations selected from this population gave a mean equal to 140.30. The population is known to have a normal distribution.
Round your answers to two decimal places.
a. Make a 99% confidence interval for μ( , )
b. Construct a 97% confidence interval for μ( , )
c. Determine a 95% confidence interval for μ( , )
d. Does the width of the confidence intervals constructed in parts a through c decrease as the confidence level decreases?
Yes
No