Question 404736: The college board reported the following mean scores for teh three parts of the SAT.
Critical Reading 502
Mathematics 515
Writing 494
Assume that the population standard deviation on each part of the test is o=100
What is the probability a random sample test of 90 test takers will provide a sample mean test score within 10 points of the population mean of 502 on the critical reading part of the test?
I have gotten [502-10, 502=10]= [492,512]
P(492
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! The college board reported the following mean scores for three parts of the SAT.
Critical Reading 502
Mathematics 515
Writing 494
Assume that the population standard deviation on each part of the test is o=100
What is the probability a random sample test of 90 test takers will provide a sample mean test score within 10 points of the population mean of 502 on the critical reading part of the test?
I have gotten [502-10, 502=10]= [492,512]
t(492) = (492-502)/[100/sqrt(90)] = -10/[100/sqrt(90)] = -0.9487
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t(512) = (512-502)/[100/sqrt(90)] = +0.9487
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P(492 < x-bar < 512) = P(-0.9487 < t < +0.9487 when df= 89) =0.6547
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Cheers,
Stan H.
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