Suppose you have a sample of 12 for which you want to constr

Suppose you have a sample of 12 for which you want to construct a normal probability plot. what is the P i and corresponding z i value for the 7th ordered sample?

Solution

Since sample size is 12, the 6th and the 7th ordered sample would be the mid points of the sample.Let us denote by X_(n), the nth ordered statistics. Thus probability that a point is below X₍₇₎ is 0.5, i.e. Pi = 0.5 and the corresponding zi = 0.000