Question

A quality control manager wants to determinate the percentage of defective light bulbs

Answer 1

in a batch of 1000 light bulbs. To do this, the manager selects a sample of 100 light bulbs and finds that 10 of them are defective.

To determine the percentage of defective light bulbs in the entire batch, the manager can use the proportion method.

First, calculate the proportion of defective light bulbs in the sample:

Defective light bulbs in sample = 10
Total light bulbs in sample = 100

Proportion of defective light bulbs in sample = Defective light bulbs in sample / Total light bulbs in sample
= 10 / 100
= 0.1

Next, use this proportion to estimate the percentage of defective light bulbs in the entire batch:

Percentage of defective light bulbs in entire batch = Proportion of defective light bulbs in sample * 100
= 0.1 * 100
= 10%

Therefore, the quality control manager can estimate that approximately 10% of the entire batch of 1000 light bulbs are defective.