SOLUTION: the average teachers salary in NJ (ranked first among states) is $52,174. Suppose that the distribution is normal with standard deviation equal to $7500. a/ What is the probabi

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Question 477789: the average teachers salary in NJ (ranked first among states) is $52,174. Suppose that the distribution is normal with standard deviation equal to $7500.
a/ What is the probability that a randomly selected teacher makes less than $50,000 a year.
b/ If we sample 100 teachers salaries, what is the probability that the sample mean is less than $50,000
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

μ =  $52,174 

σ =  $7500

a) z = (50,000-52,174)/7500 = -.2899  NORMSDIST(-0.2899) = .386 OR 38.6%

b) z = -2174/[7500/sqrt(100)]  = -2.8987  NORMSDIST(2.8987)= .0019 OR .19 %