Question

Data were collected during the time period in which a constant number of checkout counters were open. The total number of customers in the store and the waiting times in minutes were recorded.

a) Use Excel to construct the scatter plot.

b) Determine the linear regression equation between a number of customers and waiting time include that on the graph

c) Predict the waiting period when there are 20 customers in the store.

d) Show r= coefficient of regression and r² =coefficient of determination on the graph

Day	Customers	Time
1	15.00	1.50
2	18.00	1.20
3	9.00	0.80
4	7.00	0.50
5	19.00	2.00
6	30.00	2.50
7	27.00	3.00
8	13.00	2.00
9	11.00	1.70
10	9.00	0.50
11	21.00	2.00
12	35.00	5.20
13	25.00	2.30
14	8.00	0.20
15	16.00	0.70
16	21.00	2.50
17	17.00	1.00
18	22.00	3.80
19	16.00	1.50
20	24.00	2.80
21	14.00	1.00
22	15.00	1.70
23	21.00	3.00
24	27.00	2.80
25	17.00	1.00
26	21.00	2.50
27	20.00	2.90
28	31.00	3.40
29	38.00	4.00
30	42.00	4.80

Answer 1

a) Use Excel to construct the scatter plot.

yF0.1285x-0.448 R2 0.7873 10 15 20 25 漠) 35 HL 45

File Ho Insest Page LaynutFormulas Data Review VieDeveloper Add-ins Help Prathu Ptrweer Pivot FurmatTell me what yeu want to do MP Add Chart Quik Change Element Layout Colors Switch Ra Select Change Meve Colun Data Chart Type Chart Chart Layouts Chart Stydes Type Location Chart 1 Format Trendline Trendline Options Time Linear 14 Laganthmic Polynomial Order 2 R-0.7873 L Average penod Trendlinee Name Lincar (Timc Automatic n0periods periods □ Set Intercept Cisplay Equaticn on chart Display R squared value on chart

b) Determine the linear regression equation between a number of customers and waiting time include that on the graph

5 y= 0.1285x-0.448 R2 0.7873 4 10 15 20 25 漠) 35 HL 45

c) Predict the waiting period when there are 20 customers in the store.

y = 0.1285x - 0.448

x = 20

y = 0.1285*20 + 0.448

y = 2.122

) Show r= coefficient of regression and r² =coefficient of determination on the graph

r Correlation = 0.8873

Formula: =CORREL(B2:B31,C2:C31)

r-squared = 0.7873 (available in the above chart)