Question

 

(a) Employers at a firm are worried about the effect of March Madness, a basketball championship held each spring in the US, on employee productivity. They estimate that on a regular business day employees spend on average 15 minutes of company time checking personal email, making personal phone calls, etc. They also collect data on how much company time employees spend on such non-business activities during March Madness. They want to determine if these data provide convincing evidence that employee productivity decreases during March Madness.

(b) Since 2008, chain restaurants in California have been required to display calorie counts of each menu item. Prior to menus displaying calorie counts, the average calorie intake of diners at a restaurant was 1100 calories. After calorie counts started to be displayed on menus, a nutritionist collected data on the number of calories consumed at this restaurant from a random sample of diners. Do these data provide convincing evidence of a difference in the average calorie intake of diners at this restaurant?

(c) Based on the performance of those who took the GRE exam between July 1, 2004, and June 30, 2007, the average Verbal Reasoning score was calculated to be 462. In 2011 the average verbal score was slightly higher. Do these data provide convincing evidence that the average GRE Verbal Reasoning score has changed since 2004?

Answer 1

(A) we want to check  if these data provide convincing evidence that employee productivity decreases during March Madness.

Null hypothesis:- employees spend 15 minutes on such non-business activities during March Madness

Alternate hypothesis:-  employees spend more than 15 minutes on such non-business activities during March Madness

(B) We want to check whether there is any difference in the average calorie intake of diners at this restaurant

Null hypothesis:_ there is no difference in the average calorie intake of diners at this restaurant

Alternate hypothesis:_ there is a significant difference in the average calorie intake of diners at this restaurant

(C) We want to test whether the average GRE Verbal Reasoning score has changed since 2004 or not.

Nulll hypothesis:_ there is no change in the average GRE Verbal Reasoning score has changed since 2004

Alternate hypothesis:- there is a significant change in the average GRE Verbal Reasoning score has changed since 2004