Question

Every 20th person in line at grocery store was asked whether they had used their price plus card today. Out of 50 people, 38 said yes. Is this a valid sampling method? If so, find how many of the 800 people in the store would be expected to be using their price plus card.

Answer 1

Yes

608 people

Explanation:

800 × 38 =30400

30400 ÷ 50 =608

Answer 2

This is an example of systematic sampling, which is a valid sampling method if the ordering of the individuals in the population does not affect the results. However, it may not be a representative sample if there is any pattern or bias in the order of the individuals.

Using the given information, we can estimate the proportion of people who have used their price plus card as:

38/50 = 0.76

Therefore, we can expect that approximately 0.76 of the 800 people in the store would be using their price plus card:

0.76 x 800 = 608 people.