Question

You measure 32 turtles' weights, and find they have a mean weight of 64 ounces. Assume the population standard deviation is 5.7 ounces. Based on this, construct a 95% confidence interval for the true population mean turtle weight. Give your answers as decimals, to two places.

Answer 1

Solution :

Given that,

Point estimate = sample mean =     = 64

Population standard deviation =    = 5.7

Sample size n =32

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z/2 = Z0.025 = 1.96   ( Using z table )

Margin of error = E =   Z/2    * ( /n)
= 1.96 * ( 5.7 / 32)

= 1.97
At 95% confidence interval
is,

- E < < + E

64 - 1.97 <   < 64+ 1.97

62.03 <   < 65.97