Answer:
Now we just take square root on both sides of the interval and we got:
Step-by-step explanation:
Information given
represent the sample mean
population mean (variable of interest)
s=2.4 represent the sample standard deviation
n=83 represent the sample size
Confidence interval
The confidence interval for the population variance is given by the following formula:
The degrees of freedom given by:
The confidence level is 0.90 or 90%, the value of and , and we can use excel, a calculator or a table to find the critical values.
The excel commands would be: "=CHISQ.INV(0.05,82)" "=CHISQ.INV(0.95,82)". so for this case the critical values are:
The confidence interval is given by:
Now we just take square root on both sides of the interval and we got: