The popping-times of the kernels in a certain brand of microwave popcorn are

normally distributed with a mean of 150 seconds and a standard deviation of

10 seconds

The first kemel pops 127 seconds after the microwave oven is started, What

is the z:score of this kernel? Round your answer to two decimal places.

The z-score for this kernel is - 2.3

Step-by-step explanation:

* Lets revise how to find the z-score

- The rule the z-score is z = (x - μ) / σ, where

# x is the score

# μ is the mean

# σ is the standard deviation

* Lets solve the problem

- The popping-times of the kernels in a certain brand of microwave

popcorn are normally distributed

- The mean is 150 seconds

- The standard deviation is 10 seconds

- The first kernel pops is 127 seconds

- We want to find the z-score for this kernel

∵ z-score = (x - μ) / σ

∵ x = 127

∵ μ = 150

∵ σ = 10

∴ z-score = (127 - 150) / 10 = - 23/10 = - 2.3

* The z-score for this kernel is - 2.3