Question

Suppose Burger King has run a major advertising campaign in the hopes of increasing monthly sales. To investigate the effectiveness of this campaign, Burger King randomly selected six restaurants and recorded the monthly sales before and after the advertising. The following data represents these sales figures in thousands of dollars.

Restaurant

1

2

3

4

5

6

After

$123

$122

$145

$156

$160

$134

Before

$107

$110

$143

$168

$145

$125

If Population 1 is defined as sales after the advertising campaign and Population 2 is defined as sales before the advertising campaign, the correct hypothesis statement for this hypothesis test would be ______________________.

a.H0: ?d = 0; H1: ?d > 0

b.H0: ?d ? 0; H1: ?d < 0

c.H0: ?d = 0; H1: ?d ? 0

d.H0: ?d ? 0; H1: ?d > 0

Answer 1

The right answer is:

a.H0: μd = 0; H1: μd > 0

Explanation:

The claim that want to be tested is that the sales were significantly increased after the commercial, indicanting that the advertisement campaign was effective.

This claim is usually expressed in the alternative hypothesis as it has to have enough evidence to prove that it is true.

Then, the alternative hypothesis H1 should state that the difference (sales after - sales before) is higher than 0.

The null hypothesis would state that the difference is not significantly different from 0, or, in other words, that the sales are the same before and after and that the variation is due to pure chance.

Then, the null hypothesis H0 would state that the difference is equal to 0.

The right answer is:

a.H0: μd = 0; H1: μd > 0