# What is normal distribution curve in SPSS research?

What is normal distribution curve in SPSS research?

### 1 comment to What is normal distribution curve in SPSS research?

• Francis

What is normal distribution curve in SPSS research?
This is a curve that shows if the variable(s) you are working on are normally distributed.
For you to know your variable(s) are normally distributed there are various ways.

FREQUENCIES.
Procedure from SPSS
Analyze menu
Frequencies
A dialogue box appears, double click the variable(s) of interest so that they appear on the box labeled variable(s), click on the chart button. The dialogue box that appears, click on Histograms and also check the sub option WITH NORMAL CURVE.
This will allow you to assess whether you data is normally distributed, for instant if the diagrams doesn’t show symmetrical curve then it’s not normally distributed

Note normal curve is symmetrically bottom bell-shaped.

HISTOGRAM

Procedure from SPSS
Graphs menu
Histogram
Double click on the variable under consideration, click on DISPLAY NORMAL CURVE sub option then click ok.

Z-SCORE
When a data is assumed to be normally distributed or the statistics assume normal distribution ten itâ€™s advisable to standardize those variables to reduce bias.

Procedure from SPSS Analyze menu
Descriptive statistics
Select the variable(s) under consideration check the box SAVE STANDARDIZED VALUES AS VARIABLES and click ok.
Now the standardized values are displayed on the data editor view. From there you can SELECT CASES that satisfy normal distribution (those that lie between -3 and 3 of the standardized value)

SELECT CASES
Procedure from SPSS Data menu
Select cases
The dialogue that appears, click on IF CONDITION IS SATISFIED then the IF button, another dialogue appear where you type you condition. After all that, the rows that satisfy the condition are selected and indicated by a diagonal line in the numbering column on the data view window. The cases that are indicated by a diagonal line are the ones used in the analysis.

Check on PP-Plots that test on various distributions.

Procedure from SPSS
Graphs menu
P-P