An Analytical Framework of a Deployment Strategy for Cloud Computing Services: A Case Study of Academic Websites

Table 13

The probability distributions of request service time obtained from NCTU records.

Service time (ms/request)	PDF of ED (𝐸)	PDF of RD (𝑂)	CDF of ED	CDF of RD	(𝐸−𝑂)^2/𝐸
[0, 12]	39.046%	76.060%	39.046%	76.060%	0.3509
(12, 24]	23.800%	18.210%	62.846%	94.270%	0.0131
(24, 36]	14.507%	4.360%	77.353%	98.630%	0.0710
(36, 48]	8.843%	1.040%	86.196%	99.670%	0.0688
(48, 60]	5.390%	0.250%	91.586%	99.920%	0.0490
(60, 72]	3.285%	0.060%	94.871%	99.980%	0.0317
(72, 84]	2.003%	0.020%	96.874%	100.000%	0.0196
(84, 96]	1.221%	0.000%	98.094%	100.000%	0.0122
(96, 108]	0.744%	0.000%	98.838%	100.000%	0.0074
(108, 120]	0.454%	0.000%	99.292%	100.000%	0.0045
(120, 132]	0.276%	0.000%	99.568%	100.000%	0.0028
(132, 144]	0.169%	0.000%	99.737%	100.000%	0.0017
(144, infinite)	0.263%	0.000%	100.000%	100.000%	0.0026
Summary					0.6354