Question

The incomes of trainees at a local mill are normally distributed with a mean of $1100 and a standard deviation of $150.
What percentage of trainees earn less than $900 a month?

Answer 1

Answer:

9.18%

Step-by-step explanation:

We have been given that the incomes of trainees at a local mill are normally distributed with a mean of $1100 and a standard deviation of $150. We are asked to find percentage of trainees that earn less than $900 a month.

First of all, we need to find the z-score corresponding to sample score pf 900.

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

$z=\frac{900-1100}{150}$

$z=\frac{-200}{150}$

$z=-1.33$

Now, we will use normal distribution table to find the area under z-score of $-1.33$ as:

$P(z<-1.33)=0.09176$

$0.09176\times 100\%=9.176\%\approx 9.18\%$

Therefore, approximately 9.18% of trainees earn less than $900 a month.