Z value (also known as z-score) is the distance (signed) between your model and a prediction.
If your model is a mean (the average), the z-scores are the set of differences between the mean and the values used to compose the mean.
If your model is a regression (relating, say, two variables relating x and y), then the z-score is the difference between the regression line and the values used to fit the regression.
Z value (also known as z-score) is the distance (signed) between your model and a prediction.
If your model is a mean (the average), the z-scores are the set of differences between the mean and the values used to compose the mean.
If your model is a regression (relating, say, two variables relating x and y), then the z-score is the difference between the regression line and the values used to fit the regression.