The Manager of a Dairy Products Division Wants to Test

Multiple Choice

The manager of a Dairy Products Division wants to test the effects of the "buy one,get one free" sales promotion on the sale of the company-owned brand of packaged cheese,for a week.She records the sales of the packaged cheese during the previous 2 weeks to assess the effect of the promotion.However,on the very day that her sales promotion goes into effect,the Dairy Farmer's Association unexpectedly launches a multimedia advertisement on the benefits of consuming dairy products,especially cheese.The sales of all dairy products,including cheese,go up in all stores,including the one where the experiment had been in progress.Here,because of unexpected advertisement,one cannot be sure how much of the increase in sales of the cheese in question was due to the sales promotion and how much to the advertisement of the Dairy Farmers' Association! In this case,___________ have reduced the internal validity or the faith that can be placed on the conclusion that the sales promotion caused the increase in sales.

A) Main testing effects.
B) Maturation effects.
C) History effects.
D) Instrumentation effects.