Stats Ch. 1-7 Review

Here is the dot plot of voter turnout (as a percentage of voting-age population) for the 50 states—plus the District of Columbia—in a recent presidential election. Which of the following best describes this distribution?

• The distribution of voter turnout is skewed slightly left, centered at about 62%, with a range of 24%.
• The distribution of voter turnout is roughly symmetric, centered at about 60%, with a range of 30%.
• The distribution of voter turnout is skewed slightly right, centered at about 62%, with a range of 24%.
• The distribution of voter turnout is bimodal, centered at about 60%, with a range of 30%.

The stem-and-leaf diagram below gives the distribution of the ages in years of 20 participants at a family reunion. Which of the following statements about the distribution is correct?

• The first quartile is larger than the third quartile.
• The distribution is strongly skewed to the left.
• It makes the most sense to use the mean and standard deviation as a numerical summary of the center and spread of this distribution.
• The mean is larger than the median.

The side-by-side boxplots show the distribution of test scores in Ms. Williams’s two sections of calculus. Based on these boxplots, which one of the following statements must be true?

• The lowest score in A period was close to the 15th percentile of the C period class.
• The mean score for students in C period was higher than the mean score for students in A period.
• More people scored between 72 and 90 in C period than scored between 72 and 81 in A period.
• The standard deviation of scores in A period is smaller than the standard deviation of scores in C period.

According to the 1.5 x IQR rule, how many outliers are there in the data set 72, 110, 114, 115, 118, 123, 144, 156?

• None
• One
• Two
• Three

A zoologist studying adult bears measures a number of different variables. Which of the possible variables is categorical (qualitative)?

• the weight in pounds of an adult bear
• the level of aggression (low, moderate, high) displayed by an adult bear
• the number of fish an adult bear eats in a particular day

An adult male aged 20-29 who is 73 inches tall would be shorter than what percent of males in his age group?

• 10%
• 15%
• 85%
• 90%

The following scatterplot describes the relationship between height (in cm) and foot length (also in cm) for 12 randomly selected students from the British Census @ Schools database. Which of the following is the best description of this relationship?

• There is some random variation, but otherwise height is directly proportional to foot length.
• There is a roughly linear relationship between height and foot length.
• There is a moderately weak, positive linear relationship between height and foot length.
• The relationship between height and foot length is linear, positive, and very strong.

Tags

CCSS.HSF.IF.B.4

Which of the following statements about the slope of the least-squares regression line is true? 

• It has the same sign as the correlation coefficient r.
• The square of the slope equals the proportion of the variation in the response variable that is explained by the explanatory variable.
• It is unitless.
• When the x-variable is 0, this is what the y-variable is predicted to be.

A study showed that students who spend more time studying for statistics tests tend to achieve better scores on their tests. In fact, the number of hours studied turned out to explain 81% of the observed variation in test scores among the students who participated in the study. What is the value of the correlation between number of hours studied and test score? 

• r = 0.81
• r = 0.656
• r = 0.9
• There is no way to know.

The following computer output describes the relationship between y = height (in cm) and x = foot length (also in cm) for 12 randomly selected students from the British Census @ Schools database. The scatterplot for this relationship show a roughly linear shape. Which of the following is an equation of least-squares regression line for these data?

• Height = 117.99 + 1.878 (Foot Length)
• Foot Length = 117.99 + 1.878 (Height)
• Height = 1.878 + 117.99 (Foot Length)
• Foot Length = 1.878 + 117.99 (Height)

Tags

CCSS.8.EE.C.8C