Question

4. This data is the total of a bill at a restaurant and how much the server is tipped for that bill.

1. Use the data to create a scatterplot of the relationship between Bill Total and Tip Given.

Bill Total	Tip Given
21.30	2.00
27.50	1.50
29.90	5.00
32.00	4.50
33.20	6.30
34.50	4.10
35.80	5.30
38.20	5.70
43.50	1.00
45.10	7.50
48.90	5.90

2. Looking at the scatterplot, what is the strength and direction of this relationship?

Strength: _________________

Direction: _________________

3. Find the correlation coefficient for this relationship. r = ______________

4. Looking at the graph, there appears to be an outlier in this data set. What bill and tip pair from the data set is the outlier?

Outlier: x = ________ and y = _________

5. Remove the outlier from the data set. Find the correlation coefficient again.

r = ______________ (without outlier)

Answer 1

1. Bring data in to excel sheet

2.Select both x and y variable and insert scatter plot chart.

с E F G H - J L K M 8.00 1.50 7.00 6.00 5.00 А. B 1 Bill Total Tip Given 2 21.30 2.00 3 27.50 4 29.90 5.00 5 32.00 4.50 6 33.20 6.30 7 34.50 4.10 8 35.80 5.30 9 38.20 5.70 10 43.50 11 45.10 7.50 12 48.90 5.90 13 14 15 16 17 18 4.00 1.00 3.00 2.00 . 1.00 0.00 0.00 10.00 20.00 30.00 40.00 50.00 60.00

1. Looking at the scatterplot, what is the strength and direction of this relationship?

Strength : Moderate strength between the variables. it seems like not a weak positive at the same time, is not a strong positive

Direction: Positive direction

Find the correlation coefficient for this relationship. r = 0.445

E 8 ху fix =CORREL(A2:A12,B2:B12) с D E F G A B 1 Bill Total Tip Given 2 21.30 2.00 3 27.50 1.50 4 29.90 5.00 5 32.00 4.50 6 33.20 6.30 7 34.50 4.10 8 35.80 5.30 9 38.20 5.70 10 43.50 1.00 11 45.10 7.50 12 48.90 5.90 r= 0.445 لا

Looking at the graph, there appears to be an outlier in this data set. What bill and tip pair from the data set is the outlier?

с D E F G H - J K L M N o P 8.00 7.00 6.00 5.00 r= 0.445 А B 1 Bill Total Tip Given 2 21.30 2.00 3 27.50 1.50 4 29.90 5.00 5 32.00 4.50 6 33.20 6.30 7 34.50 4.10 8 35.80 5.30 9 38.20 5.70 10 43.50 11 45.10 7.50 12 48.90 5.90 13 14 15 16 17 18 19 4.00 1.00 3.00 2.00 . 1.00 0.00 0.00 10.00 20.00 30.00 40.00 50.00 60.00

x = 43.50 ; y = 1.00

This is the outlier value from the scatterplot

1. Remove the outlier from the data set. Find the correlation coefficient again.

r = 0.787 (without outlier)

E8 fx =CORREL(A2:A11, B2:B11) וד с D E G WN 4 5 А B 1 Bill Total Tip Given 21.30 2.00 3 27.50 1.50 29.90 5.00 32.00 4.50 6 33.20 6.30 7 34.50 4.10 8 35.80 5.30 9 38.20 5.70 10 45.10 7.50 11 48.90 5.90 12 ON r= 0.787 0 00 13 14