Stat old tests

A five-number summary for a data set is 35, 50, 60, 70, 90. About what percent of the observations are between 35 and 90? 100% 50% 25% 75%

100%

A five-number summary given in Case Study 1.1 for the fastest ever driving speeds reported by 102 women was: 30, 80, 89, 95, 130. What is the interquartile range (IQR) of these data? 15 100 9 6

15

If an exam was worth 100 points, and your score was at the 80th percentile, then: your score was 80 out of 100. 20% of the class had scores at or above your score. 20% of the class had scores at or below your score. 80% of the class had scores at or above your score.

20% of the class had scores at or above your score.

A regression between foot length (response variable in cm) and height (explanatory variable in inches) for 33 students resulted in the following regression equation: y ^ = 10.9 + 0.23 x What is the predicted foot length for a student who is 73 inches tall? 17.57 cm 33 cm 27.69 cm 29 cm

27.69 cm

A list of 5 pulse rates is: 70, 64, 80, 74, 92. What is the median for this list? 77 74 76 80

74

In a survey, students are asked how many hours they study in a typical week. A five-number summary of the responses is: 2, 9, 14, 20, 60. Which interval describes the number of hours spent studying in a typical week for about 50% of the students sampled? 9 to 14 2 to 9 14 to 20 9 to 20

9 to 20

Which one of the following variables is a quantitative variable? Hair color Gender Age Marital status (e.g., single, married, divorced, etc.)

Age

What is the effect of an outlier on the value of a correlation coefficient? An outlier will always increase a correlation coefficient. An outlier will always decrease a correlation coefficient. An outlier will have no effect on a correlation coefficient. An outlier might either decrease or increase a correlation coefficient, depending on where it is in relation to the other points.

An outlier might either decrease or increase a correlation coefficient, depending on where it is in relation to the other points.

Which one of these variables is a categorical variable? Number of ear piercings Weight Brand of car Height

Brand of car

A counselor at a weight-loss clinic believes that depression has an effect on body mass index (BMI). He gathers data from 45 subjects and finds the coefficient of determination (r2) between these two variables to be .453. What does this mean? BMI explains 45.3% of the variation in depression. Depression explains 45.3% of the variation in BMI. Depression explains 54.7% of the variation in BMI. BMI explains 54.7% of the variation in depression.

Depression explains 45.3% of the variation in BMI.

Which one of the following statements involving correlation is possible and reasonable? The correlation between hair color and eye color is 0.80. The correlation between hair color and age is positive. The correlation between the height of a father and the height of his first son is 0.6 The correlation between left foot length and right foot length is 2.35.

The correlation between the height of a father and the height of his first son is 0.6

Which one of the following statements is most correct about a skewed dataset? The mean and median will usually be different. The mean and median will usually be the same. The mean will always be lower than the median. The mean will always be higher than the median.

The mean and median will usually be different.

You wish to describe the relationship between exam grades and the amount of time students watch the Discovery Channel. The correlation turns out to be r = +0.30. What does this mean? 30% of the variation in exam grades is explained by the linear relationship with time spent watching the Discovery Channel. In order to increase your exam grades, it is recommended that you spend more time watching the Discovery Channel. The more a student watches the Discovery Channel, the lower his or her exam grades tend to be. The more a student watches the Discovery Channel, the higher his or her exam grades tend to be.

The more a student watches the Discovery Channel, the higher his or her exam grades tend to be.

Which one of the following is a variable that we usually put on the horizontal axis of a scatterplot? response variable explanatory variable y variable dependent variable

explanatory variable

The simple linear regression equation can be written as y ^ = b 0 + b 1 x. In the simple linear regression equation, the symbol y ^ represents the: estimated slope predicted response estimated intercept explanatory variable

predicted response

Two variables have a positive association or relationship when: the values of one variable tend to decrease as the values of the other variable increase. the values of one variable tend to increase regardless of how the values of the other variable change. the values of both variables are always positive. the values of one variable tend to increase as the values of the other variable increase.

the values of one variable tend to increase as the values of the other variable increase.