SOLUTION: The credit score of a 35 year old applying for a mortgage is normally distributed with a mean of 600 abd a standard deviation of 100. A) Find the credit score that defines the

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Question 255132: The credit score of a 35 year old applying for a mortgage is normally distributed with a mean of 600 abd a standard deviation of 100.
A) Find the credit score that defines the upper 5 percent.
B) Seventy- five percent of customers will have a credit score higher than what value?
C) In what range would the middle 80 percent of credit scores lie.
Please help! thanks
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
The credit score of a 35 year old applying for a mortgage is normally distributed with a mean of 600 abd a standard deviation of 100.
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A) Find the credit score that defines the upper 5 percent.
The cutoff z-score is 1.645
Use x = zs+u to find the raw score.
x = 1.645*100+600
x = 164.5+600
x = 764.5
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B) Seventy- five percent of customers will have a credit score higher than what value?
That would be the left-tail cutoff for 25%:
That z is invNorm(0.25) = -0.6745
x = -0.6745*100+600
x = -67.45+600
x = 532.55
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C) In what range would the middle 80 percent of credit scores lie.
That is a left-tail cutoff at 10% and a right-tail cutoff at 90%
z = invNorm(0.10) = -1.2816 and z = +1.2816
I'll let you figure out the x values.
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Cheers,
Stan H.