Question

1. A consumer products researcher randomly surveyed 800 people and asked them if they try to avoid eating fast food. Of the 455 respondents who were 34 or younger, 191 said they did. Of the 345 who were 35 or older, 180 said they did.

1. Use Minitab to test at the 1% level for a difference in fast food avoidance between these two age groups.
2. Interpret the test results in the context of the data and the question being studied.

How might the results of this test be used by a fast food company?

Answer 1

Test and CI for Two Proportions

Method

p₁: proportion where Sample 1 is younger than 34 = Event

p₂: proportion where Sample 2 is older than 35 = Event

Difference: p₁ - p₂

Descriptive Statistics

Sample	N	Event	Sample p
Sample 1	455	191	0.419780
Sample 2	345	180	0.521739

Estimation for Difference

Difference	99% CI for Difference
-0.101959	(-0.193340, -0.010578)

CI based on normal approximation

Test

Null hypothesis	H₀: p₁ - p₂ = 0
Alternative hypothesis	H₁: p₁ - p₂ ≠ 0

Method	Z-Value	P-Value
Normal approximation	-2.87	0.0041

____________________________________________________________

Since p-value is less than 0.01, so we can conclude that the two groups are different