A real estate company wants to evaluate two of their home appraisers for consistency in preparation for their annual state certification. It is important that different appraisers be able to give similar estimates for homes and other properties. The company selects a random sample of 10 homes in different neighborhoods around the city and independently asks each appraiser for an estimate of the home value. After they receive the estimates for each home, the company subtracts the value given by the first appraiser from the value given by the second appraiser. They create a Q-Q plot of the differences and see that the points in the plot roughly form a straight line. Are the requirements for using the desired confidence interval satisfied? Explain. A. Yes. The distribution of mean differences is normal because the sample size is large.
B. Yes. The distribution of mean differences is normal because the data have been determined to be normal.
C. No. The distribution of mean differences is not normal because the sample size is not large enough.
D. Not necessarily, because the company needs to check that the values given by each appraiser are normal, not that the differences are normal.

Now suppose the company of the previous question wants to use a hypothesis test to determine whether the estimates given by the two appraisers are different. Which of the following would be the most appropriate pair of hypotheses for such a test?

A. H0:μ1=μ2
Ha:μ1≠μ2
B. H0:μ1≠μ2
Ha:μ1=μ2
C. H0:μd=0
Ha:μd≠0
D. H0:μd≠0
Ha:μd=0

A salesman for a shoe company claimed runners would run faster races if they wore the company's brand of running shoe. A track coach wanted to see how much faster his runners would run, if they wore the company's shoes. He randomly selected 8 runners and had each of them run the 100-yard dash, twice. They wore their usual shoes to run the race on one day, and they wore the company's shoe to run the race on another day. Their times for both races were recorded, and the coach randomly selected the day each runner would wear the company's brand of shoe. Which confidence interval would be most appropriate for this study?

A. One sample z-confidence interval
B. One sample t-confidence interval
C. Paired-samples t-confidence interval
D. Two sample t-confidence interval

Suppose you create a 95% confidence interval for a mean, and get (-2.346, 8.775). You've been told to report this by saying, "We are 95% confident that the true mean is between -2.346 and 8.775." Exactly what does this mean?

A. There is a 95% chance that the true mean is between -2.346 and 8.775.
B. 95% of all 95% confidence intervals actually contain the true mean.
C. 95% of the data are between -2.346 and 8.775.
D. 95% of the sample means are between -2.346 and 8.775.

Which one of the following is a correct statement of the Central Limit Theorem?

A. The Central Limit Theorem is only applicable in hypothesis testing.
B. x¯ , if n is sufficiently large.
C. There are limits to how accurate we can measure the center of a distribution.
D. The distribution of x¯will be approximately normal if n is sufficiently large.