However, I have a question. I know it is very simple for you but I am just not sure what is the right way of doing so. This is just frequency and percentage, not really advance stat analysis etc. But how should I specifically handle this case: we ask the sample if they have business, if yes it will proceed to question like “did you already already accessed loan?”. Say having business is 256, but next question shows that accessed loan=100 and did not accessed=150 which means there is 6 is missing. How this case should be dealt particularly on computing the percent frequency? should it be accessed loan: 100/250 or 100/256??
The formula for the standard deviation is the one given on the webpage http://-/descriptive-statistics/measures-variability/ . Or you can use the Excel formula STDEV as usual. In the case of the paired t test you calculate the standard deviation on the difference between the data values for the two samples (as shown in Figure 2 of http://-/students-t-distribution/paired-sample-t-test/ ). The standard error is then this value divided by the square root of the sample size, as explained right after Figure 2.
If you download the Real Statistics Examples Workbook you can access the spreadsheets for all the examples on the website. From these spreadsheets you can see how all the calculations are done.