Notation and Numerical Calculations for With Trend Over Time
Notation | Formula | Calculated Value |
---|---|---|
Within-lot estimate of slope | ![]() | β̂ = −0.457 |
Variance of predicted lot means | ![]() | SL2 = 4.197 |
Mean squared error | ![]() | SE2 = 0.529 |
Predicted value of Y at t0 | Ŷ = Ȳ* + β̂(t0 − t̄*) | 66.333 at t0 = 12 |
Estimated variance of Ŷ at t0 | ![]() | 0.648 at t0 = 12 |
Estimated variance of Y | ![]() | 4.363 |
Harmonic mean of the number of values in each lota | ![]() | 1.454 |
Lot degrees of freedom | s = I − 1 | 10 |
Error degrees of freedom | ![]() | 14 |
Effective sample size | ![]() | 6.729 at t0 = 12 |
Upper bound on variance of Y | ![]() | 10.820 |
Constants used to compute U where χα:s2 and χα:r2 are chi-squared percentiles with area α to the left and s and r degrees of freedom, respectively | C1 = s/χα:s2 − 1 | 1.538 |
C2 = r/χα:r2 − 1 | 1.131 | |
Lower bound on one-sided tolerance interval | Equation 6 | L1 = 57.36 |
Upper bound on one-sided tolerance interval | Equation 7 | U1 = 75.31 |
Lower and upper on two-sided tolerance interval | Equation 8 | L2 = 57.25, U2 = 75.41 |
Lower and upper one-sided bounds using HK1 adjustment of two-sided tolerance interval | Equation 8 replacing ![]() | L1,HK1 = 58.13, U1,HK1 = 74.53 |
↵a This is an adjustment from the value suggested by Park and Burdick (18) but is computationally easier and provides very similar results.