The manager of the customer service division of a consumer electronics company was interested in determining whether customers who had purchased a DVD player over the past 12 months were satisfied with their products. Using the warranty cards submitted after purchases, the manager was planning to survey these customers. If the manager wanted to select a sample of warranty cards for each brand of DVD player sold, how should the sample be selected?Explain

Answer 1

The manager should use stratified sampling to select a sample of warranty cards for each brand of DVD player sold. Stratified sampling involves dividing the population into distinct groups, or strata, based on a specific characteristic - in this case, the brand of DVD player.

Here's a step-by-step process of selecting the sample using stratified sampling:

1. Identify the different brands of DVD players sold by the company in the past 12 months.
2. For each brand, create a separate list of warranty cards submitted by customers.
3. Determine the sample size for each brand. The manager can either select an equal sample size for each brand or use proportionate sampling, in which the sample size for each brand is proportional to the number of warranty cards submitted for that particular brand.
4. Use a random sampling method (such as simple random sampling) to select the desired number of warranty cards from each brand's list.
5. Combine the selected warranty cards from all brands to create the final sample.

By using stratified sampling, the manager ensures that each brand of DVD player is represented in the sample, which would provide more accurate insights into customer satisfaction across different brands.