Find the indicated probability or percentage for the normally distributed variable.
-The incomes of trainees at a local mill are normally distributed with a mean of $1,100 and a standard deviation $150. What percentage of trainees earn less than $900 a month?
A)35.31%
B)40.82%
C)90.82%
D)9.18%

Question

Find the indicated probability or percentage for the normally distributed variable.
-The incomes of trainees at a local mill are normally distributed with a mean of $1,100 and a standard deviation $150. What percentage of trainees earn less than $900 a month? 
A)35.31%
B)40.82%
C)90.82%
D)9.18%

Quizplus · Accepted Answer

To find the percentage of trainees earning less than $900 a month, we calculate the z-score using the formula $z = \frac{X - \mu}{\sigma}$, where $X = 900$, $\mu = 1100$, and $\sigma = 150$. This gives us $z = \frac{900 - 1100}{150} = -\frac{200}{150} = -1.33$. Looking up -1.33 on the standard normal distribution table or using a calculator, we find that approximately 9.18% of trainees earn less than $900 a month.

Find the Indicated Probability or Percentage for the Normally Distributed