Table 6. Flight simulated instrument flight evaluation
t
-test by service classification
Group
Obs
Mean
Std. Dev.
95% Conf. Interval
Short term
79
19.394
9.161
17.342 21.446
Long term
51
23.925
3.592
22.914 24.935
Diff
-4.530
-7.194 -1.866
diff = mean(0) - mean(1)
t
= -3..364
Ho: diff = 0 degrees of freedom = 128
Ha: diff < 0
Pr(T<
t
) = 0.0005
**Ha: diff != 0
Pr(|T|>|
t
|) = 0.001
Ha: diff > 0
Pr(T>
t
) = 0.999