Question

3. Suppose that n =100 random samples of water from a freshwater lake were taken and the calcium concentration (milligrams per liter) measured. A 95% CI on the mean calcium concentration is (0.49 ≤ µ ≤ 0.82).

a) Would a 99% CI calculated from the same sample data be longer or shorter, explain your answer?

b) Consider the following statement: There is a 95% chance that µ is between 0.49 and 0.82. Is this statement correct? Explain your answer.

c) Given the information that the σ = 5.6, find the sample size needed to compute a 90% CI of width 2.3.

Answer 1