# Please tell me about the properties of probability density function used in SPSS research

Please tell me about the properties of probability density function used in SPSS research

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Probability density function is a table, a graph or an equation that links each out come of a statistical experiment with its probability of occurrence.

SPSS researcher first take diagnostic test before carrying on with the analysis, and for this matter you have to know which distribution your data set is following. In this case test for distribution by either using P-P plots or the non parametric test (one sample kolmogorov Smirnov test).
Procedure from Graphs menu, P-P…, a dialog box of P-P plots appears where select the variable(s) of interest and test for the distribution. The second option procedure is, from analyze menu, Non parametric tests, 1sample K. S. test. The dialog that appears gives only four types of distribution to be tested.

It’s advisable to the SPSS researchers to first analyze descriptive statistics which are vital in computation of probability density functions. Some of these parameters used are mean and standard deviation. Other parameters that may be required in accordance with the distribution are probability of success p, probability of failure q, etc.
Now I will give you the answer to your question.

SPSS can be used to compute the probability density function of normal, chi square, log normal, Beta, Gamma, Poisson, binomial, among others that you will see if you follow the following procedure.

From the SPSS Transform menu, compute. A dialogue box appears named compute variable. Name your target variable as PDF. In the same dialogue box there is a sub dialog box labeled functions, scroll down until you start to see the word PDF followed by the distribution you are dealing with. Select the PDF under consideration and click the arrow facing up so that it appears on the Numeric expression box. It will appear with question marks which you are supposed to fill with the appropriate parameters according to the distribution. Then click ok.