True or False? When choosing the sample size for estimating a population proportion p to within E units with confidence (1 - a)100, if you take p 0.
5 as the approximation to p, you will always obtain a sample size that is at least as large as required. A) True B) False
Q. 2Find the area under the standard normal curve between z = 1 and z = 2.
A) 0.1359 B) 0.8413 C) 0.5398 D) 0.2139
Q. 3Two conditions are required to test a claim about two population standard deviations. What are they?
A) The samples are independent and the population is normal.
B) The samples are mutually exclusive and the population is normal.
C) The samples are independent and the populations are randomly selected.
D) The samples are mutually exclusive and the population are randomly selected.
Q. 4Find the standardized test statistic, z, to test the hypothesis that p1 ? p2. Use a = 0.02. The sample statistics listed below are from independent samples. Sample statistics: n1 = 1000, x1 = 250, and n2 = 1200, x2 = 195
A) 5.087 B) 2.798 C) 4.761 D) 3.212
Q. 5In a college student poll, it is of interest to estimate the proportion p of students in favor of changing from a quarter-system to a semester-system. How many students should be polled so that we can estimate p to within 0.
09 using a 99 confidence interval? A) 205 B) 182 C) 261 D) 114
Q. 6True or False: The variance of a population is the arithmetic average of the squared deviations about the population mean.
A) True B) False
Q. 7Find the standardized test statistic, z, to test the hypothesis that p1 < p2. Use a = 0.10. The sample statistics listed below are from independent samples. Sample statistics: n1 = 550, x1 = 121, and n2 = 690, x2 = 195
A) -2.513 B) -2.132 C) -0.985 D) 1.116
Q. 8Many people think that a national lobby's successful fight against gun control legislation is reflecting the will of a minority of Americans. A previous random sample of 4000 citizens yielded 2250 who are in favor of gun control legislation.
How many citizens would need to be sampled if a 90 confidence interval was desired to estimate the true proportion to within 4? A) 417 B) 440 C) 423 D) 389
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