Question

What is the z-score for Σx = 840?

Short answer

The z-score for Σx = 840 is approximately 26

Step-by-step solution

Given Information

Given that details, the sample size of customers is 400 with a mean of 3 and the standard deviation is $0.7$. The sum of values is 840, so the$Z$-score is given as:

Explanation

The sum of values is 840, so the$Z$-score is given as:

$840=400\times 3+\left(z\right)\times \sqrt{400}\times 0.7$

$-360=14.0\left(z\right)$

$z=25.714$

$z=26$