Graph a Scatter Plot and Find the Correlation

Name______Date______Class______

Scatter Plots and Trend Lines

Practice and Problem Solving: A/B

Graph a scatter plot and find the correlation.

1.The table shows the number of juice drinks sold at
a small restaurant from 11:00 am to 1:00 pm.
Graph a scatter plot using the given data.

Time / 11:00 / 11:30 / 12:00 / 12:30 / 1:00
Number of Drinks / 20 / 29 / 34 / 49 / 44

2.Name the two variables. ______

3.Write positive, negative, or none to describe the correlation
illustrated by the scatter plot you drew in problem 1. Estimate
the value of the correlation coefficient, r. Indicate whether r is
closer to 1, 0.5, 0, 0.5, or 1.

______

A city collected data on the amount of ice cream sold in the city each day and the amount of suntan lotion sold at a nearby beach each day.

4.Do you think there is causation between the city’s two variables? If so, how? If not, is there a third variable involved? Explain.

______

Solve.

5.The number of snowboarders and skiers at a resort per day and the amount of new snow the resort reported that morning are shown in
the table.

Amount of New Snow (in inches) / 2 / 4 / 6 / 8 / 10
Number of Snowsliders / 1146 / 1556 / 1976 / 2395 / 2490

a.Make a scatterplot of the data.

b.Draw a line of fit on the graph above and find the equation

for the linear model. ______

c.If the resort reports 15 inches of new snow, how many skiers and
snowboarders would you expect to be at the resort that day?

______

Name______Date______Class______

Linear Modeling and Regression

LESSON 10-1

Practice and Problem Solving A/B

2. time, number of drinks

3. positive; r is close to 1.

4. Sample answerNo; the temperature will probably influence both.

5. a.

b.y 176x 854

c.3494; Students’ answers should be
correct for the equations they found in
the step above.

Practice and Problem Solving C

2. Possible answer

y 1.44x 4; r 1

3. y 1.568x 2.787; r 0.925

4. The answers are close. Estimating, I got a y-intercept of 4 and the calculator found 3 (rounded). Estimating, my slope was 1.44, and the calculator found 1.568, a difference of about 8%. The calculator is more accurate; it provides the best fit. Estimating, I can only get close.