Carmen Homework 4 - Scatterplots and Correlation

A researcher is trying to determine the January temperature in regions of the United States using the degrees of latitude. After collecting data, she creates the scatterplot above. Which of the following is the most likely value of r, the correlation coefficient, for the data?

-0.87

Suppose you have 4 data sets whose scatterplots all show possible linear relationships. The four data sets have correlations of -0.10, +0.25, -0.90, and +0.80, respectively. Which of the correlations shows the strongest linear relationship?

-0.90

The personnel department keeps records on all employees in a company. Here is the information they keep in one of their data files: Employee identification number Last name First name Middle initial Department Number of years with the company Salary Education (coded as high school, some college, or college degree) Age Which of the following combinations of variables would be appropriate to examine with a scatterplot?

Age and Salary

A researcher is trying to determine the January temperature in regions of the United States using the degrees of latitude. After collecting data, she creates the scatterplot above. Which of the following is the correct interpretation of the correlation depicted in the scatterplot?

There is a moderately strong negative linear relationship between temperature and latitude.

A researcher is trying to determine the January temperature in regions of the United States using the degrees of latitude. After collecting data, she creates a scatterplot. Given the relationship the researcher is trying to predict, the latitude is the dependent variable and the temperature is the independent variable.

False

If the correlation coefficient, r, between two variables is 0, we can conclude that there is no relationship between the two variables.

False

If you switch X and Y the sign of the correlation changes.

False

Suppose the correlation between X =price of a gallon of gaspline and Y = price of a gallon of milk is r = .40. Then the correlation between the price of a HALF gallon of milk and the price of a HALF gallon of gas must be r = .4/2 = .20.

False

The units of r, the correlation coefficient, are the same as the X variable.

False

A STAT 1430 student is interested in examining the relationship between the number of bedrooms in a home and it's selling price. After downloading a valid data set from the internet, the student creates a scatterplot and calculates the correlation. The correlation value they calculate is 0.67. This implies that the selling price of a house tends to increase as the number of bedrooms increases.

True