Lesson 8

Analyzing Bivariate Data

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Problem 1

Different stores across the country sell a book for different prices. The table shows the price of the book in dollars and the number of books sold at that price.

price in dollars number sold
11.25 53
10.50 60
12.10 30
8.45 81
9.25 70
9.75 80
7.25 120
12 37
9.99 130
7.99 100
8.75 90
A blank coordinate plane with 21 horizontal units and 29 vertical units.
  1. Draw a scatter plot of this data. Label the axes.
  2. Are there any outliers? Explain your reasoning.
  3. If there is a relationship between the variables, explain what it is.
  4. Remove any outliers, and draw a line that you think is a good fit for the data.

Solution

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Problem 2

Here is a scatter plot:

A scatterplot, age in weeks, weight in pounds. From origin, points trend up & right with a consistent slope to around 24 comma 60. From x = 30 to x = 120, points are clustered around the line y = 60.

Select all the following that describe the association in the scatter plot:

A:

Linear association

B:

Non-linear association

C:

Positive association

D:

Negative association

E:

No association

Solution

For access, consult one of our IM Certified Partners.

(From Unit 6, Lesson 7.)

Problem 3

Using the data in the scatter plot, what can you tell about the slope of a good model?

A scatterplot. Horizontal, from 1980 to 2020, by 10’s. Vertical, from 90 to 115, by 5’s. 14 data points trend slightly linearly downward and right.
A:

The slope is positive.

B:

The slope is zero.

C:

The slope is negative.

D:

There is no association.

Solution

For access, consult one of our IM Certified Partners.

(From Unit 6, Lesson 6.)