Question

You measure 33 textbooks' weights, and find they have a mean weight of 53 ounces. Assume the population standard deviation is 9.1 ounces. Based on this, construct a 99% confidence interval for the true population mean textbook weight.

Give your answers as decimals, to two places

< μμ <

Box 1: Enter your answer as an integer or decimal number. Examples: 3, -4, 5.5172
Enter DNE for Does Not Exist, oo for Infinity

Box 2: Enter your answer as an integer or decimal number. Examples: 3, -4, 5.5172
Enter DNE for Does Not Exist, oo for Infinity

Answer 1

We have given that,                          
                          
Sample mean =53   ounces              
Population standard deviation=9.1 ounces              
Sample size=33                  
Level of significance =   1-0.99=   0.01                  
Z critical value (by using Z table)=2.58              
                          
Confidence interval formula is


=(48.92,57.08)                          
                          
Lower confidence limit =48.92          
Upper confidence limit =57.08         

Therefore,