While using itemfit() function for missing data, the output showed some extra entities with SD_ character below the item fit statistics. Assuming that it stand for stand deviation I compared the entities with the formula, looks like something is not right.
ave[pick1, pick2] <- SD[pick1, pick2] <- 0
Here you are calculating sum(Xi), which is fine
for (i in 1L:impute) ave[pick1, pick2] <- ave[pick1,
pick2] + collect[[i]][pick1, pick2]
Here it is average ( sum(Xi)/n) which is also fine.
ave[pick1, pick2] <- ave[pick1, pick2]/impute
But here, you are only taking square over the difference (ave(Xi) - Xi), where is the sum over i part ?
for (i in 1L:impute) SD[pick1, pick2] <- (ave[pick1,
pick2] - collect[[i]][pick1, pick2])^2
SD[pick1, pick2] <- sqrt(SD[pick1, pick2]/impute)
Thanking you,
Irshad