Question

You measure 29 turtles' weights, and find they have a mean weight of 38 ounces. Assume the population standard deviation is 3.2 ounces. Based on this, construct a 99% confidence interval for the true population mean turtle weight. Give your answers as decimals, to two places

Answer 1

Solution :

Given that,

sample mean = = 38

Population standard deviation =    = 3.2
Sample size = n =29

At 99% confidence level the z is ,

  = 1 - 99% = 1 - 0.99 = 0.01

/ 2 = 0.01 / 2 = 0.005

Z/2 = Z0.005 = 2.576   ( Using z table )

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

= 2.576 * (3.2 / 29)

= 1.53

At 99% confidence interval estimate of the population mean is,

- E < < + E

38-1.53 < < 38+1.53

36.47< < 39.53

(36.47 , 39.53)