Suppose that I am looking at a
- Suppose that I am looking at a sample of 30 students cominginto the university. The individual scores, X, on the collegeentrance examination are normally distributed with a mean of 550and a standard deviation of 100.
a. Suppose the mean of those 30 students is 575. What is thepercentile score of that mean?
b. What is the probability that the mean will be at least 600for a set of 30 students?
Answer:
µ = 550
sd = 100
n = 30
a)
= P(Z < 1.37)
= 0.9147
= 91.47 percentile
b)
= P(Z > 2.74)
= 1 – P(Z < 2.74)
= 1 – 0.9969
= 0.0031