Question

you measure 25 turtles weights, and find they have a mean weight of 45 ounces. assume the population standard deviation is 4.2 ounces. Based on this, construct a 90% confidence interval for the true population mean turtle weight.

Answer 1

Given that, population standard deviation = 4.2 ounces

sample size (n) = 25 and sample mean = 45 ounces

A 90% confidence level has significance level of 0.10 and critical value is, Zc = 1.645

The 90% confidence interval for the true population mean turtle weight is,

45 - (1.645 * 4.2 / √(25)) < μ < 45 + (1.645 * 4.2 / √(25))

45 - 1.3818 < μ < 45 + 1.3818

43.6182 < μ < 46.3818

Therefore, required confidence interval is, (43.6182, 46.3818) ounces.

​​​​​​