In: Math
The scores of students on the SAT college entrance examinations at a certain high school had a normal distribution with mean μ=548.8μ=548.8 and standard deviation σ=26.4σ=26.4.
(a) What is the probability that a single student randomly
chosen from all those taking the test scores 555 or higher?
ANSWER:
For parts (b) through (d), consider a simple random sample (SRS) of
35 students who took the test.
(b) What are the mean and standard deviation of the sample mean
score x¯x¯, of 35 students?
The mean of the sampling distribution for x¯ is:
The standard deviation of the sampling distribution for x¯ is:
(c) What z-score corresponds to the mean score x¯ of 555?
ANSWER:
(d) What is the probability that the mean score x¯ of these
students is 555 or higher?
ANSWER:
Refer Z-table to find the probability or use excel formula "=NORM.S.DIST(0.23, TRUE)" to find the probability.
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From part (c), z=1.39
Refer Z-table to find the probability or use excel formula "=NORM.S.DIST(1.39, TRUE)" to find the probability.