Question

In a market test of a new chocolate raspberry coffee, a poll of 400 people (sample 1) from Dobbs Ferry showed 250 preferred the new coffee. In Irvington, 170 out of 350 people (sample 2) preferred the new coffee. To test the hypothesis that a higher proportion of people in Dobbs Ferry prefer the new coffee, what is the test statistic?

Answer 1

Solution:

Given:

Sample 1: Dobbs Ferry

n₁ = 400

x₁ = Number of people preferred the new coffee = 250

Sample 2: Irvington

n₂ = 350

x₂ = Number of people preferred the new coffee = 170

We have to find the test statistic:

Formula:

where

and

Thus

Thus the test statistic is: