Chapter 1. Tutorial: Correlation

Problem Statement

A dataset consists of the composition of 77 breakfast cereals – a portion of the dataset is shown below.

Calories – calories / serving;

Protein, Fat, Fiber, Total Carbohyrates, Sugars – grams/serving.

Here is plot of the relationship between the calories/serving and the number of grams of fat.

Step 1

questions

Question 1

Correlation measures the strength of the relationship between two variables.

Correct.
Incorrect.

Step 2

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Question 4

In the plot of breakfast cereals above, there appears to be correlation between the calories/serving and the grams of fat/serving.

Correct.
Incorrect.

Step 3

Consider the following plots of the correlation between two variables:

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Question 8

The correlation in (a) is about .

Correct.
Incorrect.

Step 4

The following is a plot of the mileage of a vehicle (miles/gallon) vs. the average speed (miles/hour).

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Question 12

There is between the average speed and mileage obtained.

Correct.
Incorrect.

Step 5

Sometimes it is hard to measure the actual values of variables, but it quite easy to give a qualitative assessment of the size. For example, consider the following table of the number of species classified by the risk of predation and typical body mass.

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Question 15

If you could measure the two variables “exactly”, the correlation between them would be about

A.
B.
C.
D.
Correct.
Incorrect.