Question

A telecommunications company commissioned a study to investigate the amount of time that people spend on phone calls. The study that found that the length of time that people spend on a phone call is approximately normally distributed with a mean of 519 seconds and a standard deviation of 104.7 seconds. Calculate the standardized value (z) for a time of 630 seconds. Give your answer to 2 decimal places

Answer 1

Answer:

$z = 1.06$

Step-by-step explanation:

Given

$\bar x = 519$ -- Mean

$\sigma = 104.7$ --- Standard Deviation

$x = 630$ --- Time

Required

Determine the standardized value (z)

The standardized value (z) is calculated using:

$z = \frac{x - \bar x}{\sigma}$

This gives:

$z = \frac{630 - 519}{104.7}$

$z = \frac{111}{104.7}$

$z = 1.06017191977$

$z = 1.06$ --- approximated