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Topic 7 Homework (Nonadaptive)

Question 7 of 16 (1 point)**|**Question Attempt: 1 of Unlimited

Dennis

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Question 7

You are the owner of Fast Break, a popular local place that sells drinks, snacks, and sandwiches. For inventory management purposes, you are examining how the weather affects the amount of hot chocolate sold in a day. You are going to gather a random sample of 

9

 days showing that day's high temperature (denoted by 

x

, in 

°C

) and the amount of hot chocolate sold that day (denoted by 

y

, in liters). You will also note the product 

·xy

 of the temperature and amount of hot chocolate sold for each day. (These products are written in the row labeled "

xy

").

(a)Click on "Take Sample" to see the results for your random sample.

Take Sample

High temperature, 

x

  (in 

°C

)

12

18

23

7

29

12

23

3

15

Amount of hot  chocolate sold, 

y

  (in liters)

10

7

11

16

5

15

8

18

12

xy

120

126

253

112

145

180

184

54

180

Send data to calculator

Based on the data from your sample, enter the indicated values in the column on the left below. Round decimal values to three decimal places. When you are done, select "Compute". (In the table below, 

n

 is the sample size and the symbol 

Σxy

 means the sum of the values 

xy

.)

n

: 

9

x

: 

142

y

: 

102

sx

: 

1354

sy

: 

2472

Σxy

: 

1434

Compute

Sample correlation coefficient (

r

):

−0.005

Slope (

b1

):

−0.01

y

-intercept (

b0

):

103.25

(b)Write the equation of the least-squares regression line for your data. Then on the scatter plot for your data, graph this regression equation by plotting two points and then drawing the line through them. Round each coordinate to three decimal places. 

Regression equation: 

y

=

Amount of hot chocolate sold (in liters)

y

2

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6

8

10

12

14

16

18

20

22

24

x

3

6

9

12

15

18

21

24

27

30

33

36

0

High temperature (in 

°C

)

(c)Use your regression equation to predict the amount of hot chocolate sold on a day with a high temperature of 

19   °C

. Round your answer to the nearest whole number. 

Predicted amount of hot chocolate sold: 

liters19

Check

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