Question

In the 1970's PepsiCo., makers of Pepsi, began airing commercials in which they claimed more cola drinkers preferred Pepsi over Coca-Cola in a blind taste test. Assume Pepsi's claim is that more than 50% of Coca-Cola drinkers prefer Pepsi. You work for an independent research firm and are asked to test Pepsi's claim.

1. Identify the null and alternative hypotheses and identify the one with the claim.
2. If 280 people from a sample of 500 prefer Pepsi, find the p-value. Will you reject or fail to reject the null hypothesis at the 5% significance level?
3. Interpret your decision in the (correct) context of the problem. Is there enough evidence to support Pepsi's claim?
4. Why do you think Pepsi used a blind taste test?

Answer 1

Here claim is that p>0.50

So hypothesis is vs

Claim is alternative hypothesis

Now

So test statistics is

P value is

As P value is less than alpha we reject the null hypothesis

Hence we have sufficient evidence to support the claim that p>0.50

Maybe as via blind test they can identify easily as color of both the drinks are same