The Next Questions Are Based on the Following Information

The Next Questions Are Based On The Following Information:
The sales representative for a manufacturer of a new product claims that the product will increase output per machine by at least 29 units per hour.A line manager installs the product on 15 of the machines,and finds that the average increase was only 26 with a standard deviation of 6.2.
-Which of the following is true of confidence intervals in hypothesis tests of the variance of a normal population,where variances are smaller than anticipated?

A) It will always result in a negative value.
B) It will meet anticipated levels.
C) It will be wider than anticipated.
D) It will be narrower than anticipated.