Correlation and Causation Basics

Describe the relationship given the stated r value.

r = -0.92

• strong and positive

• strong and negative

• weak and positive

• weak and negative

Describe the relationship given the stated r value.

r = 0.89

• strong and positive

• strong and negative

• weak and positive

• weak and negative

Describe the relationship given the stated r value.

r = 0.34

• strong and positive

• strong and negative

• weak and positive

• weak and negative

When a correlation is strong, what do we know about the line of best fit?

• The dots are scattered far from the line.

• The dots are close to the line.

• The line is horizontal.

Professor Maths notices that there is a strong, positive correlation between the number of water fountains on campus and the standardized test scores of the students. What does this mean?

• As the number of water fountains increases, the standardized test scores decrease.

• As the number of water fountains decreases, the standardized test scores decrease.

• As the number of water fountains decreases, the standardized test scores increase.

• As the number of water fountains increases, the standardized test scores increase.

Professor Maths notices that there is a strong, positive correlation between the number of water fountains on campus and the standardized test scores of the students. He says, "this strong correlation indicates a causal relationship between the number of water fountains and test scores."

Is he right? Why or why not?

• Yes, the increase in test scores is a result of the water fountains.

• Yes, all strong, positive correlations indicate causation.

• No, there could be other factors that are affecting standardized test scores.

• No, the correlation would have to be negative in order for this to be true,

Professor Maths also notes that there is a strong correlation between the number of cups of coffee his students drink and their daily homework points. He calculates the line of best fit for the data as

y = 3.1 x + 1.2

Interpret the slope in this situation.

• For every 1 cup of coffee, daily homework scores increase by 3.1 points.

• For every 3.1 cup of coffee, daily homework scores increase by 1 points.

• For every 1 cup of coffee, daily homework scores increase by 1.2 points.

• For every 1 cup of coffee, daily homework scores decrease by 3.1 points.

Describe the slope of the line of best fit where the r value is - 0.77.

• positive

• negative

Which two things are least likely to be associated?

• Outside temperature and number of people wearing hats.

• Height and shoe size.

• The number of pencils in a classroom and the number of students who complete their homework.

• The number of hours studied and the score received on the test.

Describe the correlation between the number of oil changes a car has and its sale price.

• strong, positive

• strong, negative

• weak, positive

• weak, negative