Question

The weekly salary paid to employees of a small company that supplies part-time laborers averages $700 with a standard deviation of $400. If the weekly salaries are normally distributed, estimate the proportion of employees that make:

a.) more than $800 per week

b.)less than $200 per week

c.)more than $200 per week

d.)between $500 and $1000 per week

Answer 1

Given that, mean (μ) = $700 and standard deviation = $400

Using standard normal z-table we find the following probabilities,

a) We want to find, P(X > 800)

Therefore, the proportion of employees that make more than $800 per week is 0.4013

b) We want to find, P(X < 200)

Therefore, the proportion of employees that make less than $200 per week is 0.1056

c) We want to find, P(X > 200)

Therefore, the proportion of employees that make more than $800 per week is 0.8944

d) We want to find, P(500 < X < 1000)

Therefore, the proportion of employees that make between $500 and $1000 per week is 0.7745