1- it's not bad practice to sort on the identified key variable and select the test records using every 2nd record and that using Stratified Sampling is however a better method?
I thought you mean taking totally randomly files every second one without sorting.
sorting probably will be good as...
I glad I could help you :)
Of course, the page is not a substituted to SPSS or R ...but it can do the job in your case and many other cases, hopefully easily...
Actually, I didn't notice it was an SPSS question ...
I tested it successfully in google chrome with 3 X columns and 50 Y...
"Hi obh, yes i believe you are referring to stratified random samples which is one of my options.
As to why every second record - I am however the whole prospect file into two 50% files therefore sorting on my key variable (say age) and taking every 2nd (even) record as the test and every odd...
I don't understand why every second record?
A simple example (hopefully I understand you correctly):
Let assume your main variable is color: 40% red, 60%blue.
You want to take a sample of 10% and change the message in this sample. (to check if the message change will influence Y)
If you know the standard deviation from the entire population you should use z-test. if you calculate the standard deviation only from the sample you should use the t-test.
Before ...can you plan your sample to have a similar key variable, instead of taking it randomly and then test it?
Generally, it is better to use the t-test if you don't know the population standard deviation. t limit to Z when n limit infinity, and when n>30 z will also give you a reasonable result. but I assume it is relevant to the time people used tables instead of computers ...
to reduce the standard...
Please don't say that about yourself :(
If you paste your data in the following link you will have a bit better explanation: http://www.statskingdom.com/420logistic_regression.html
If you still have a specific question please let me know
I assume that you want to standardized the data before performing the regression.? It should not be a problem.
Do you need both standardize and not standardized?
I will check tomorrow. Please check my answer tomorrow :)
Coefficients are there (coeff in the second table) .
Generally, you need to check in "Residuals Table" or/and " ANOVA Table" or/and... to get more data.
I assume it should be okay now.
If still not okay, can you please show an example of how you like it to be? (includes the residuals) and I...