# How do I make a normal quantile plot in JMP?

How do I make a normal quantile plot in JMP?

## How do I make a normal quantile plot in JMP?

Select the data column and click Y. Select the column with the group indicator and click X. Click OK to launch Oneway. Click the red triangle next to Oneway and select one of the commands to plot the normal quantiles.

What does a normal quantile plot tell you?

The quantile-quantile (q-q) plot is a graphical technique for determining if two data sets come from populations with a common distribution. A q-q plot is a plot of the quantiles of the first data set against the quantiles of the second data set.

What is the Y axis of a normal quantile plot?

The normal plot is clearer. It shows the observations on the X axis plotted against the expected normal score (Z-score) on the Y axis. It’s not necessary to understand what an expected normal score is, nor how it’s calculated, to interpret the plot.

### How do I show quantiles in JMP?

In JMP the quantiles are specified in the Tables/Summary/ panel. You select the variable for which you want the quantiles and modify the quantiles percentage which is set by default to 25 and then choose Quantiles from the Statistics puldown menu. Grouping can also be set in the obvious manner.

How do you draw a normal probability plot?

How to Draw a Normal Probability Plot

1. Arrange your x-values in ascending order.
2. Calculate fi = (i-0.375)/(n+0.25), where i is the position of the data value in the. ordered list and n is the number of observations.
3. Find the z-score for each fi
4. Plot your x-values on the horizontal axis and the corresponding z-score.

What does a good normal QQ plot look like?

The normal distribution is symmetric, so it has no skew (the mean is equal to the median). On a Q-Q plot normally distributed data appears as roughly a straight line (although the ends of the Q-Q plot often start to deviate from the straight line).

## How do you interpret a Q-Q plot?

If the bottom end of the Q-Q plot deviates from the straight line but the upper end is not, then we can clearly say that the distribution has a longer tail to its left or simply it is left-skewed (or negatively skewed) but when we see the upper end of the Q-Q plot to deviate from the straight line and the lower and …

How do I know if my data is normally distributed JMP?

From an open JMP® data table, select Analyze > Distribution. 2. Select one or more continuous variables from Select Columns and click Y, Columns.