Find the 90% confidence interval for the population standard deviation given the following.

n = 51, x = 11.49, s = 2.34 and the distribution is normal.

a. 1.92 < σ < 3.25
b. 2.01 < σ < 2.81
c. 1.37 < σ < 1.91
d. 10.28 < σ < 14.32

b. 2.01 < σ < 2.81

Step-by-step explanation:

The 90% confidence interval for the population standard deviation is calculated as:

   < σ <

Where n is equal to 51, s is equal to 2.34, is 10%, is the value for the Chi squared distribution with n-1 degrees of freedom that has a probability of in the right tail and is the value for the Chi squared distribution with n-1 degrees of freedom that has a probability of in the right tail.

So, replacing n by 51, s by 2.34, by 67.50 and by 34.76, we get that the The 90% confidence interval is equal to:

< σ <

2.01 < σ < 2.81

72 is the answer to this problem

step-by-step explanation:

you can add the two numbers and divide the result by 2. or you can find the gap between the two numbers and add half of this to the smaller number.