Used to assess if a data set follows a normal distribution.
Steps for Creating
1. Order each observation smallest to largest, recording the percentile for each observation.
2. Using Table A or invNorm(, find the z-scores for each percentile.
3. Plot each observation x against its expected z-score.
If the line created is roughly linear, the distribution is normal. Only pay attention to systematic deviations from the line, not few far away points, which are outliers.