Download Unit 5 Multiple Choice

AP Statistics - Chapter 5B Warm-Ups
11. A simple random sample of 50 undergraduates at Johns Hopkins University found that 60% of those sampled felt
that drinking was a problem among college students. A simple random sample of 50 undergraduates at Ohio State
University found that 70% felt that drinking was a problem among college students. The number of undergraduates
at Johns Hopkins University is approximately 2000, while the number at Ohio State is approximately 40,000. We
conclude that
A) the sample from Johns Hopkins has much less variability than that from Ohio State
B) the sample from Johns Hopkins has much more variability than that from Ohio State
C) the sample from Johns Hopkins has almost the same variability as that from Ohio State
D) it is impossible to make any statements about the variability of the two samples since the students surveyed were
different
23. A random sample of size 25 is to be taken from a population that is normally distributed with mean 60 and
standard deviation 10. The average J of the observations in our sample is to be computed. The sampling
distribution of J is
A) normal with mean 60 and standard deviation 10
B) normal with mean 60 and standard deviation 2
C) normal with mean 60 and standard deviation 0.4
D) normal with mean 12 and standard deviation 2
25. An automobile insurer has found that repair claims have a mean of $920 and a standard deviation of $870. Suppose
that the next 100 claims can be regarded as a random sample from the long-run claims process. The mean and
standard deviation of the average J of the next 100 claims is
A) mean = $920 and standard deviation = $87
B) mean = $920 and standard deviation = $8.70
C) mean = $92 and standard deviation = $87
D) mean = $92 and standard deviation = $870
32. Suppose that you are a student worker in the statistics department and they agree to pay you using the Random Pay
system. Each week the chair of the department flips a coin. If it comes up heads, your pay for the week is $80; if it
comes up tails, your pay for the week is $40. Your friend is working for the engineering department and makes
$65 per week. The probability that your total earnings in 100 weeks are more than hers is approximately
A) 0.0000
B) 0.4013
C) 0.5000
D) 0.5987
34. The weights of extra-large eggs have a normal distribution with a mean of 1 ounce and a standard deviation of 0.1
ounces. The probability that a dozen eggs weighs more than 13 ounces is closest to
A) 0.0000
B) 0.0020
C) 0.1814
D) 0.2033
The SAT scores of entering freshmen at University X have a N(1200, 90) distribution, and the SAT scores of entering
freshmen at University Y have a N(1215, 110) distribution. A random sample of 100 freshmen is sampled from each
university, with J the sample mean of the 100 scores from University X and M the sample mean of the 100 scores from
University Y.
38. The probability that J is less than 1190 is
A) 0.0116
B) 0.1335
C) 0.4090
D) 0.4562
39. The probability that M less than 1190 is
A) 0.0116
B) 0.1335
C) 0.4090
D) 0.4562
Answer Key
7. D
8. D
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A
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