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Question

# Suppose x has a distribution

with a mean of 90 and a standard deviation of 36. Random samples of size n = 64

are drawn.

(a) Describe the x distribution

and compute the mean and standard deviation of the distribution.

x

has

---Select---

an approximately normal

a Poisson

an unknown

a geometric

a binomial

a normal

distribution with mean μx =

and standard deviation σx =

.

(b) Find the z value corresponding to x = 81.

z =

(c) Find P(x < 81).

P(x < 81) =

(d) Would it be unusual for a random sample of size 64 from the x distribution to have a sample mean less than 81? Explain.

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