MATH 1070-070: Quiz 4
June 12, 2008
Name:
No outside materials are allowed except pens, pencils, erasers, and calculators. You have one
half hour to complete this quiz. Please keep nervous ticks to a minimal so as to not disrupt
anyone else taking the quiz. Anyone caught cheating will be punished with a grade of 0%.
You may need the following:
z=
x−µ
σ
For X, a binomial random variable:
P (x) =
n!
px (1 − p)n−x
x!(n − x)!
µX = np
p
σX = np(1 − p)
p
estimate of p = p̂, sep̂ = p̂(1 − p̂)/n, p̂ ± z(se)
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1. For an SAT distribution ( µ = 500, σ = 100) and an ACT distribution (µ = 21, σ = 4.7), which score
is relatively higher, an SAT score of 600 or an ACT of 25? Explain.
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2. For the normal height distribution of adult females in North America (µ = 65 inches, σ = 3.5 inches),
find the proportion who are
(a) under five feet (60 inches)
(b) over six feet (72 inches)
(c) between 60 and 70 inches
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3. A random-digit dialing sample of 2092 adults found that 1318 used the internet. Produce a 95%
confidence interval for the proportion of all adults who use the internet.
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