Estimated and actual costs for projects

Do the bids tend to under-estimate labour costs?


The two examples show how the paired t-test is conducted using the differences, d.

Estimated and actual costs for projects

Music and work efficiency

Age when children with heart disease start to talk

Is a construction company underestimating the costs of the projects for which it is bidding? The actual labour costs for 20 recently completed projects (in thousands of hours) and the estimated costs at the time of the bid were...

Project Actual Estimate Difference
(actual - estimate)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
9.5
6.3
18.2
3.7
25.0
26.5
23.6
8.5
8.0
21.0
9.8
11.3
10.7
13.2
3.4
13.3
9.2
16.7
14.4
15.9
4.4
8.4
14.3
0.9
24.6
25.4
23.8
3.4
3.2
19.5
4.9
11.9
9.4
7.9
5.7
14.8
6.5
18.0
12.4
12.9
5.1
-2.1
3.9
2.8
0.4
1.1
-0.2
5.1
4.8
1.5
4.9
-0.6
1.3
5.3
-2.3
-1.5
2.7
-1.3
2.0
3.0

Music and work efficiency

Does music in a warehouse affect productivity? Efficiency ratings of 15 employees recorded before and after the music system was installed.