Prob Stats Final Review

The histogram shows the heights of 300 randomly selected high school students. Which of the following is the best description of the shape of the distribution of heights?

• Roughly symmetric and single-peaked (unimodal)

• Roughly symmetric and double-peaked (bimodal)

• Roughly symmetric and multi-peaked (multimodal)

• Skewed to the left

• Skewed to the right

Two measure of center are marked on the curve. Which of the following is correct?

• The median is at the yellow line and the mean is at the red line.

• The mean is at the yellow line and the median is at the red line.

• The mode is at the red line and the median is at the yellow line.

• The mode is at the yellow line and the median is at the red line.

• The mode is at the red line and the mean is at the yellow line.

The weights of laboratory cockroaches can be modeled with a normal distribution having mean 80 grams and standard deviation 2 grams. The following figure is the normal curve for this distribution of weights. About what percent of the cockroaches have weights between 76 and 84 grams?

• 99.7%

• 95%

• 68%

• 47.5%

• 34%

The weights of laboratory cockroaches can be modeled with a normal distribution having mean 80 grams and standard deviation 2 grams. The following figure is the normal curve for this distribution of weights. About what proportion of cockroaches will have weights greater than 83 grams?

• 0.0228

• 0.0668

• 0.1587

• 0.9332

• 0.0772

The Dallas Mavericks won the NBA championship in the 2010-2011 season. The two-way table displays the relationship between the outcome of each game in the regular season and whether the Mavericks scored at least 100 points. Which of the following is the best evidence that there is an association between the outcome of a game and whether or not the Mavericks scored at least 100 points?

• The Mavericks won 57 games and lost only 25 games.

• The Mavericks scored at least 100 points in 47 games and fewer than 100 points in only 35 games.

• The Mavericks won 43 games when scoring at least 100 points and only 14 games when scoring fewer than 100 points.

• The Mavericks won a higher proportion of games when scoring at least 100 points (43/47) than when they scored fewer than 100 points (14/35).

• The combination of scoring 100 or more points and winning the game occurred more often (43 times) than any other combination of outcomes.

You look at ads for houses in Naples, Florida. There are many houses ranging from $200,000 to $500,000 in price. The few houses on the water, however, are priced up to $15 million. The distribution of house prices will be

• skewed to the left.

• roughly symmetric.

• skewed to the right.

• single-peaked.

• approximately uniform.

The scores on a statistics test had a mean of 81 and a standard deviation of 9. One students was absent on the test day, and his score wasn't included in the calculation. If his score of 84 was added to the distribution of scores, what would happen to the mean and standard deivation?

• Mean will increase, and standard deviation will increase.

• Mean will increase, and standard deviation will decrease.

• Mean will increase, and standard deviation will stay the same.

• Mean will decrease, and standard deviation will increase.

• Mean will decrease, and standard deviation will decrease.

Jorge's score on Exam I in his statistics class was at the 64th percentile of the scores for all students. His score falls

• between the minimum and the first quartile.

• between the first quartile and the median.

• between the median and the third quartile.

• between the third quartile and the maximum.

• at the mean score for all students.

Scores on the ACT college entrance exam follow a bell-shaped distribution with mean 21 and standard deviation 5. Wayne's standardized score on the ACT was -0.6. What was Wayne's actual ACT score?

• 3

• 13

• 16

• 18

• 24

George's average bowling score is 180; he bowls in a league where the average for all bowlers is 150 and the standard deviation is 20. Bill's average bowling score is 190; he bowls in a league where the average is 160 and the standard deviation is 15. Who ranks higher in his own league, George or Bill?

• Bill, because his 190 is higher than George's 180.

• Bill, because his standardized score is higher than George's.

• Bill and George have the same rank in the leagues, because both are 30 pins above the mean.

• George, because his standardized score is higher than Bill's.

• George, because the standard deviation of bowling scores is higher in his league.