To calculate SXX, we need to sum up the squared values of x:
SXX = Σ(x^2)
SXX = 0^2 + 25^2 + 50^2 + 75^2 + 100^2 + 125^2 + 150^2 + 175^2 + 200^2 + 225^2 + 250^2 + 275^2 + 300^2 + 325^2 + 350^2 + 375^2 + 395^2
SXX = 0 + 625 + 2500 + 5625 + 10000 + 15625 + 22500 + 30625 + 40000 + 50625 + 62500 + 75625 + 90000 + 105625 + 122500 + 140625 + 156025 + 247025
SXX = 253,023.5294
Therefore, SXX is approximately 253,023.5294.
Two processes for hydraulic drilling rock are dry drilling and wet drilling. In a dry hole, compressed air is forced down the drill rods to cuttings and drive the hammer; in a wet hole, water is forced down. An experiment was conducted to determine whether the time y it takes to dry drill a distance of 5 feet in rock increases with depth x. The results for one portion of the experiment are shown in the following table.
Depth at which drilling begins: x (feet)
Time to Drill 5 feet: y
0
25
50
75
100
125
150
175
200
225
250
275
300
325
350
375
395
4.90
7.41
6.19
5.57
5.17
6.89
7.05
7.11
6.19
8.28
4.84
8.29
8.91
8.54
11.79
12.12
11.02
Calculate SXX
253 023.5294
3 640.4647
83.1462
29 656.15
1 081.3975
1 answer
1 answer