Question

Work standards specify time, cost, and efficiency norms for the performance of work tasks. They are typically used to monitor job performance. In one distribution center, data were collected to develop work standards for the time to assemble or fill customer orders. The table below contains data for a random sample of 9 orders.

Time (mins.)	Order Size
27	36
15	34
71	255
35	103
8	4
60	555
3	6
10	60
10	96

1. Construct a simple linear regression of the data using SPSS. What is the equation of the least squares line? Use time as the dependent variable.
2. In general, we would expect the mean time to fill an order to increase with the size of the order. Do the data support this theory? Test using α = .05.

Answer 1

Steps to be followed

1) Go to variable view --> Enter variable name as Time and Order-Size

2) Enter the data in data view

3) Go to Analyze--> Regression--> Linear

4) Dependent Variable as Time--> Independent variable as Order_Size

5) Click on OK

You will get following output

Model Summary
Model	R	R Square	Adjusted R Square	Std. Error of the Estimate	Change Statistics
					R Square Change	F Change	df1	df2	Sig. F Change
1	.797a	.636	.584	15.717	.636	12.214	1	7	.010
a. Predictors: (Constant), Order_size

ANOVAa
Model		Sum of Squares	df	Mean Square	F	Sig.
1	Regression	3017.122	1	3017.122	12.214	.010b
	Residual	1729.100	7	247.014
	Total	4746.222	8
a. Dependent Variable: Time
b. Predictors: (Constant), Order_size

Coefficientsa
Model		Unstandardized Coefficients		Standardized Coefficients	t	Sig.	95.0% Confidence Interval for B
		B	Std. Error	Beta			Lower Bound	Upper Bound
1	(Constant)	12.594	6.588		1.912	.098	-2.984	28.173
	Order_size	.109	.031	.797	3.495	.010	.035	.183
a. Dependent Variable: Time

Since coefficient of order size is positive it shows that as order size increases Time will Increase .. and to support this p value is 0.010 which is less than 0.05 hence we can say that there is significant impact of the order size on Time

i.e one unit increase in order_Size will increase Time by 0.109 times of one unit

Regression line is given by

Time = 12594 + 0.109*(Order_Size)

INPUT FILE