Question

In: Statistics and Probability

A population of 40 year-old females has a mean salary of $39,321 with a standard deviation...

A population of 40 year-old females has a mean salary of $39,321 with a standard deviation of $2,120. If a sample of 100 women is taken:

a) What is the probability their mean salaries will be less than $39,000?

b) What is the probability their mean salaries will be between $38000 and $39,000?

Solutions

Expert Solution

Solution :

Given that ,

= / n = 2120 / 100 = 212

a)

P( < $39000) = P(( - ) / < (39000 - 39321) / 212)   

P(z < -1.51)

= 0.0655

Probability = 0.0655

b)

= P[(38000 - 39321) /212 < ( - ) / < (39000 - 39321) / 212)]

= P(-6.23 < Z < -1.51)

= P(Z < -1.51) - P(Z < -6.23)

= 0.0655 - 0

= 0.0655

Probability = 0.0655  


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