In: Statistics and Probability
The costs (in millions) of 26 construction projects at a large industrial facility are given below.
0.707 0.918 1.143 1.240 1.553 2.003 3 .692 4.069 4.324 5.292 7.214 7.642 10.523 13.371 14.577 14.837 15.317 15.320 20.099 21.571 27.973 29.522 30.028 34.100 38.173 51.284
Is there sufficient evidence to conclude that the median cost for construction projects at this facility is under 20 million dollars? (α = 0.05)
Sign Test:
H0: The median cost for construction projects at this facility is not under 20 million dollars
H1: The median cost for construction projects at this facility is under 20 million dollars
Let the los be alpha = 5%
From the given data
S.No. | X | X-Median |
1 | 0.707 | -19.293 |
2 | 0.918 | -19.082 |
3 | 1.143 | -18.857 |
4 | 1.24 | -18.76 |
5 | 1.553 | -18.447 |
6 | 2.003 | -17.997 |
7 | 3.692 | -16.308 |
8 | 4.069 | -15.931 |
9 | 4.324 | -15.676 |
10 | 5.292 | -14.708 |
11 | 7.2147 | -12.7853 |
12 | 7.642 | -12.358 |
13 | 10.523 | -9.477 |
14 | 13.371 | -6.629 |
15 | 14.577 | -5.423 |
16 | 14.837 | -5.163 |
17 | 15.317 | -4.683 |
18 | 15.32 | -4.68 |
19 | 20.099 | 0.099 |
20 | 21.571 | 1.571 |
21 | 27.973 | 7.973 |
22 | 29.522 | 9.522 |
23 | 30.028 | 10.028 |
24 | 34.1 | 14.1 |
25 | 38.173 | 18.173 |
26 | 51.284 |
31.284 |
The number of positive signs S+ = 18
The number of negative signs S- = 8
Thus we conclude that the median cost for construction projects at this facility is not under 20 million dollars