Exam 6: Exploring Data: Relationships

Use the following Table to answer the Questions: Hours spent partying per week (x) 10 40 0 5 60 20 12 GPA (y) 3.4 0.5 3.9 3.7 4.0 1.3 3.1 -What is the slope of the regression line?

Use the following scatterplot to answer the Questions: -What conclusions can you reach if you hear 18 chirps a minute?

A data set has $\bar{x}$ = 5, $\bar{y}$ = 10, S_x = 2, S_y = 3 . What is the standardized value of $x$ =7?

If the least-squares regression line is y = 3x − 5, the value y = 1 is predicted for what value of x?

Suppose a scatterplot shows four clusters at each corner of the plot. What can you say about the feasibility of using a least-squares regression line to describe these data?

Can outliers significantly affect the least-squares regression line?

A university admissions counselor wishes to predict the performance of freshmen by considering their SAT scores. Which variable, freshman GPA or SAT score, would be the explanatory variable in a least squares regression equation?

Use the following scatterplot to answer the Questions: -What can you say about the slope of the least-squares regression line?

Is it possible for the correlation for a scatterplot to change dramatically when a single point is moved?

If the units of measurement change to larger units, then the correlation:

Below is the scatterplot for data collected on two variables. Would a least-squares regression equation be useful in describing the relationship between the variables? Why or why not?

Use the table below to answer the following Questions . Temperature in degrees F(y) 70 72 74 75 81 82 83 84 89 93 Chirps per second (x) 15 15 15 16 17 17 16 17 19 20 -What is the correlation between the variables?

Use the table below to answer the following Questions . Temperature in degrees F(y) 70 72 74 75 81 82 83 84 89 93 Chirps per second (x) 15 15 15 16 17 17 16 17 19 20 -Let x = number of chirps per second and y = temperature. How many points are above the regression line?

Max is collecting baseball cards. He has 65 cards that his aunt gave him for his birthday, and he buys 20 more each week. The total number y of cards that Max has after x weeks is given by which of the following equations?

A data set has $\bar{x}$ = 2, $\bar{y}$ = 7, S_x = 3, S_y = 3 r = 0.95 Which of the following point is on the least-squares regression line?

Use the following scatterplot to answer the Questions: -What can you say about the correlation of the data?

Use the following data to answer the Questions: 66 118 50 99 73 120 69 121 72 123 65 108 62 111 -What type of association exists between the variables on the scatterplot?

A typing service keeps data on the number of pages (x) in a manuscript and the length of time (y) (in hours) it takes to complete the typing. The least-squares regression line for the data is given by y = 20 + 0.273x. Use this to predict the amount of hours needed to type a 40-page manuscript.

If two variables named x and y have a strong positive association, then:

If the x and y coordinates of a scatterplot are exchanged, the intercept of the regression line: