Question: The best statistic for estimating a parameter has which of the following characteristics?

Answer: D. Low Bias, low variability

Question: Which of the following best describes a sampling distribution?

Answer: E. A probability distribution that describes the relative likelihood of all possible values of a statistic.

Question: In a large population of adults, the mean IQ is 112 with a standard deviation of 20. Suppose 200 adults are randomly selected for a market research campaign. The sampling distribution of the sample mean IQ is

Answer: C. Approximately Normal, mean 112, standard deviation 1.414

Question: Suppose you are sampling distribution that is strongly skewed left. Which of the following statements about the sampling distribution of the sample mean is true?

Answer: A. As the sample size increases, the shape of the sampling distribution gets closer to a Normal distribution.

Question: A polling organization announces that the proportion of American voters who favor congressional term limits is 64%, with a 95% confidence margin of error of 3%. Which of the following statements is a correct interpretation of 95% confidence?

Answer: B. There is a 95% probability that the true percent of voters favoring term limits is between 61% and 67%.

Question:

Answer: E. 38,416

Question: A 95% confidence interval for the mean reading achievement score for a population of third-grade students is (44.2,54.2). Suppose you compute a 99% confidence interval using the same data. Which of the following statements is correct?

Answer: C. The 99% interval is wider.

Question: The weights of 9 men have x-bar = 175 pounds and a standard deviation of s= 15 pounds. What is the standard error of the mean?

Answer: C. 5

Question: A significance test was performed to the null hypothesis H₀: µ=2 versus the alternative hypothesis Ha: µ≠2. A sample size of 28 produced a test statistic of t=2.051. Assuming all condition for inference were met, which of the following intervals contains a P-value for this test?

Answer: E. 0.05≤P<0.10

Question: You collect test scores on four members of a population which you can safely assume is Normally distributed and test the hypotheses Ho: µ=100 vs. Ha: µ>100. You then obtain a P-value of 0.052. Which of the following statements is true?

Answer: C. There is evidence against Ho, and a study using a larger sample size may be worthwhile.