u₂: customs brokerage service at BKK

v₁

normally = H = 0.9

v₂

very = H² = 0.81

v₃

a little = H^1/2 = 0.95

number of experts

15

1

4

u₂

mean

Standard deviation

sample size

confidence level

confidence interval

0.9055

0.030344513

20

0.95

0.9055 ± 0.013

result of calculation: u₂ ≈ v₁