Chapter 11, Problem 4P

Summary Introduction

Interpretation:

The sample size needed if the standard time estimate is to be within 5 percent of the true mean 99 percent of the time, and the percentage increase in the sample size for the higher position.

Concept Introduction:

The formula for the number of observation is,

  $n\ge {\left[\left(\frac{z}{a}\right)\left(\frac{s}{\overline{x}}\right)\right]}^2$

Here, n is the number of observation for the particular task, z is the standard deviation, ‘a’ is the confidence level of the task, s is the actual standard deviation of the sample and $\overline{x}$ is the mean of the sample observation.