Scatterplot and line of fit review

Scatterplot and line of fit review

Types of correlation

Outliers, gaps and clusters

Multiple Choice

What type of correlation does this scatter plot show?

• positive

• negative

• no correlation

• nonlinear association

Multiple Choice

What type of association does this graph have?

• positive

• negative

• none

• all of the above

Multiple Choice

What is the type of correlation?

• Negative

• no correlation

• positive

Multiple Choice

Does this data show a “linear” or “nonlinear” association?

• linear

• nonlinear

Multiple Choice

Which graph shows “clustering?”

Multiple Choice

Which of these points appears to be an “Outlier?”

• A

• B

• C

• D

Multiple Choice

What type of correlation would you likely see with:

The amount of time spent working compared to the amount of money earned

• positive correlation

• negative correlation

• no correlation

Multiple Choice

About how many male math teachers were there in 2006?

• 15

• 30

• 35

• 45

Lines of fit

The best line of fit goes through the center of the data, following the trend of the scatterplot

Multiple Choice

Which graph shows a line of best fit for the scatter plot?

• Graph A

• Graph B

• Graph C

• Graph D

Multiple Choice

Which of the following lines represents the line of best fit for the scatter plot?

• A

• B

• C

• D

Multiple Choice

What is the general trend of this line graph?

• The more you mow, the less money you make.

• You make the same amount of money regardless of how long you mow.

• The more you mow, the more money you make.

• Mowing is dangerous.

Multiple Choice

What is a line of best fit used for?

• To make predictions

• To make the graph look pretty

• To connect the points

• To make it look like you know what you are doing

Estimate the line

 $m=\frac{y_{2\ }-y_2}{x_2-x_1}$  

 $m=\frac{8-5}{2-8}=\frac{3}{-6}=-\frac{1}{2}$  

Solve for b using a point, or use graph to find b.

 $y=-\frac{1}{2}x+9$  

Multiple Choice

Suppose a LINE OF BEST FIT passes through the points (4, 8) and (6, 2). The SLOPE of this line is . . .?

• -3

• -6

• 4

• 2

Points: (4,8) and (6,2)

 $m=\frac{y_2-y_1}{x_2-x_1}=\frac{8-2}{4-6}=\frac{6}{-2}=-3$  

Multiple Choice

Which of the following could be a possible line of best fit for the data?

• y = -5/2x + 20

• y = -x + 19

• y = x + 20

• y = 2/3x + 15

Choices:

A: y = -5/2x + 20

B: y = -x + 19

C: y = x + 20

D: y = 2/3x + 15 

Eliminate C and D because of their slopes

Test A and B to see which looks closer to the data points

Multiple Choice

A restaurant sells pizza for the prices in the data table. Calculate the linear regression equation of the data.

• y = 1.5x + 12

• y = 12x + 1.5

• y = 0.67x - 8

• y = -8x + 0.67

y = 1.5x + 12

Multiple Choice

What is the line of best fit?

• f(x)= 5x+1.82

• cannot be determined

• f(x)= 1.82x + 5.02

• f(x)= 1.1x + 4.2

y=1.82x+5.02

Multiple Choice

What does an r value of r = 0.9997 imply?

• Strong positive correlation

• Weak positive correlation

• Strong negative correlation

• Weak negative correlation

Multiple Choice

The linear regression equation is y = 61.93x - 1.79. Use the equation to predict how far this person will travel after 10 hours of driving.

• 10 miles

• 617.5 miles

• 0.19 miles

• 500 miles

y=61.93x - 1.79

Plug in 10 for x

y=61.93(10) - 1.79

= 619.3 - 1.79

= 617.5

Any last minute questions?