Question

A set of electric toothbrush prices are normally distributed with a mean of 87 dollars and a standard deviation of

Answer 1

Answer:

The proportion of electric toothbrush prices are between 104.60 dollars and 108.20 dollars is 0.0099

Step-by-step explanation:

A set of electric toothbrush prices are normally distributed with a mean of 87 dollars and a standard deviation of  8 dollars.

$Mean = \mu = 87$

Standard deviation = $\sigma = 8$

We are supposed to find proportion of electric toothbrush prices are between 104.60 dollars and 108.20 dollars i.e.P(104.60<x<108.20)

$Z=\frac{x-\mu}{\sigma}$

At x = 104.60

$Z=\frac{104.60-87}{8}$

Z= 2.2

At x=108.20

$Z=\frac{108.20-87}{8}$

Z= 2.65

Refer the z table for p value :

P(x<108.20)-P(x<104.60)=P(Z<2.65)-P(Z<2.2)=0.9960-0.9861=0.0099

Hence The proportion of electric toothbrush prices are between 104.60 dollars and 108.20 dollars is 0.0099