Question

You measure 24 textbooks' weights, and find they have a mean weight of 35 ounces. Assume the population standard deviation is 14.4 ounces. Based on this, construct a 95% confidence interval for the true population mean textbook weight.

Give your answers as decimals, to two places

< μ <

Answer 1

Solution :

Given that,

= 356

= 14.4

n = 24  

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z_/2 = Z_0.025 = 1.96

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

= 1.96* (14.4 / 24)

= 5.76

At 95% confidence interval of the population mean is,

- E < < + E

35-5.76< <35+5.76

29.24< < 40.76

(, )