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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) 1 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. 2 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 3 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. 4