Describing and Summarizing Quantitative Variables

Here are the amounts of money (cents) in coins carried by 10 students in a statistics class: 50, 35, 0, 97, 76, 0, 0, 87, 23, 65. To make a stem plot of these data, you would use stems

• 0, 2, 3, 5, 6, 7, 8, 9.

• 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

• 0, 3, 5, 6, 7.

• 00, 10, 20, 30, 40, 50, 60, 70, 80, 90.

The histogram below 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 unimodal

• Roughly symmetric and bimodal

• Roughly symmetric and multimodal

• Skewed to the left

You look at real estate 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, have prices up to $15 million. The distribution of house prices will be

• skewed to the left.

• roughly symmetric.

• skewed to the right.

• Unimodal

When comparing two distributions, it would be best to use relative frequency histograms rather than frequency histograms when

• the distributions have different shapes.

• the distributions have different spreads.

• the distributions have different centers.

• the distributions have different numbers of observations.

Which of the following is the best reason for choosing a stem plot rather than a histogram to display the distribution of a quantitative variable?

• Stem plots allow you to split stems; histograms don’t.

• Stem plots allow you to see the values of individual observations.

• Stem plots are better for displaying very large sets of data.

• Stem plots make it easier to determine the shape of a distribution.

If a distribution is skewed to the right with no outliers,

• mean < median.

• mean > median.

• mean = median.

• We can’t tell without examining the data

The scores on a statistics test had a mean of 81 and a standard deviation of 9. One student 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 deviation?

• 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.

Which of the following boxplots best matches the distribution shown in the histogram?

• 
• 
• 
• 

The stem plot shows the number of home runs hit by each of the 30 Major League Baseball teams in 2011. Home run totals above what value should be considered outliers?

• 222

• 229

• 229 and 257

• 257

Remove the high outlier

• The Standard Deviation increases
• The Standard Deviation stays the same
• The Standard Deviation decreases
• The Standard Deviation is 11.87