สถิติ - ค่าสัมประสิทธิ์ความน่าเชื่อถือ

$ {Reliability \ Coefficient, \ RC = (\ frac {N} {(N-1)}) \ times (\ frac {(Total \ Variance \ - Sum \ of \ Variance)} {Total Variance})} $

P0-T0 = 10 
P1-T0 = 20 
P0-T1 = 30 
P1-T1 = 40 
P0-T2 = 50 
P1-T2 = 60

The average score of Task (T0) = 10 + 20/2 = 15 
The average score of Task (T1) = 30 + 40/2 = 35 
The average score of Task (T2) = 50 + 60/2 = 55

Variance of P0-T0 and P1-T0: 
Variance = square (10-15) + square (20-15)/2 = 25
Variance of P0-T1 and P1-T1: 
Variance = square (30-35) + square (40-35)/2 = 25
Variance of P0-T2 and P1-T2: 
Variance = square (50-55) + square (50-55)/2 = 25

Total of Individual Variance = 25+25+25=75

Variance= square ((P0-T0) 
 - normal score of Person 0) 
 = square (10-15) = 25
Variance= square ((P1-T0) 
 - normal score of Person 0) 
 = square (20-15) = 25 
Variance= square ((P0-T1) 
 - normal score of Person 1) 
 = square (30-35) = 25 
Variance= square ((P1-T1) 
 - normal score of Person 1) 
 = square (40-35) = 25
Variance= square ((P0-T2) 
 - normal score of Person 2) 
 = square (50-55) = 25 
Variance= square ((P1-T2) 
- normal score of Person 2) 
 = square (60-55) = 25

Total Variance= 25+25+25+25+25+25 = 150

$ {Reliability \ Coefficient, \ RC = (\ frac {N} {(N-1)}) \ times (\ frac {(Total \ Variance \ - Sum \ of \ Variance)} {Total Variance}) \\ [ 7pt] = \ frac {3} {(3-1)} \ times \ frac {(150-75)} {150} \\ [7pt] = 0.75} $