A quality control engineer wants to determine what proportion of defective parts are coming off the assembly line. Past experiments based on large sample sizes show this proportion to be 0.19. What sample size does the engineer need in order to estimate this proportion with a margin of error of 0.12 with 90% confidence?
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Margin of Error

A measure of the accuracy of a public opinion poll, representing the extent to which the results could vary from the true population values.

Sample Size

The count of observations or duplicates that are part of a statistical sample.

Quality Control

The process of ensuring that products and services meet consistent standards and requirements through various checks and measures.