7. Incorrect. The answer is true.

(a) 95% confidence interval is given by and .

For v=200-1=199 degrees of freedom, find

 

Therefore, and

Then the 95% confidence limits are and hours respectively.

 

(b) 99% confidence interval limits are given by and .

 

For v=200-1=199 degrees of freedom, find

 

 

 

 

 

Therefore, and

 

Then the 99% confidence limits are and hours respectively.