Database Reference
In-Depth Information
FIGURE 10.4
Commands to the Linear Regression dialog box; SPSS with illustrative example.
Using the circled coeficients in
Figure 10.7
, we produce the following least-
squares line (see values in the oval in
Figure 10.7
):
Yc=−100
.
185+1
.
104
*
Ptask1+0
.
127
*
Ptask2+0
.
903
*
Ptask3
=−100
.
185+1
.
104*80+0
.
127*100+0
.
903*100
=−100
.
185+88
.
32+12
.
7+90
.
3
= 91
.
135
Your best estimate for the time it would take the person to perform the Major Task,
given the component task times of 80, 100, and 100, respectively, is 91.135 seconds.
10.4
A CONFIDENCE INTERVAL FOR THE PREDICTION
Of course, whenever a prediction is made, be it through simple regression or multiple
regression, it is important to ind a conidence interval for the prediction.
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