Homework SourseThe scores of 12th grade students on the National Assessment
The scores of 12th grade students on the National Assessment ofEducational Progress year 2000 math test have a distribution that\'sapproximately Normal with mean =300 and standard deviation =35.Given an SRS of four 12th graders, what is the probability thattheir mean score is higher than 335?
Solution
standard deviation, =35
since an SRS of four 12th graders are taken, hence n = 4
hence standard error, e = / n = 35/2 =17.5
probability that their mean score is higher than 335,=P(X>335)
P(Z>(X-)/e) = P(Z>(335-300)/17.5)
=P(Z>2) = 1-0.9772 = 0.0228
