Using Responses and # of Responses to Back into Standard Deviation?

[maldito]

Hope this is the right location! 

I have some data I'm trying to run t-tests on, but have to get creative with backing into the data to get the SD. I have the frequency distribution and N sizes, but not individual level data. What I've done so far (in excel, since I don't know how in SAS) is multiply the N size by the percent that answered each question either a 1,2,3,4,or 5 to determine what # of people in each group responses a certain way to each question (Sheet 1) and then transposed it to the format I *THINK* SAS will want it in (Sheet 2). It looks something like this

Question_Answer	Response	Group_1	Group_2	Group_3
Q0A1	1	50	200	50
Q0A2	2	100	0	25
Q0A3	3	25	25	50
Q0A4	4	75	25	25
Q0A5	5	50	25	50
Q1A1	1	0	50	25
Q1A2	2	100	50	100
Q1A3	3	100	75	0
Q1A4	4	25	75	25
Q1A5	5	75	25	50

From here I need to get the standard deviation of each question for each group and am at a total loss of how to do that. I'm not sure if I should keep the Question column parsed out the way it is (Question 1 Answer 1, Question 1 Answer 2) or just repeat Question1 for five rows and let the response column do the heavy lifting. 

Any help would be greatly appreciated! 

[Reeza]

Is there a reason GROUP3 for Q0A1-5 doesn't add up to 300 like Group1/2? How should they add up here?

Standard deviation is usually used for continuous measurements, not categorical data. Can you explain a little more what you're looking to achieve here?

---

@maldito wrote:

Hope this is the right location! 

I have some data I'm trying to run t-tests on, but have to get creative with backing into the data to get the SD. I have the frequency distribution and N sizes, but not individual level data. What I've done so far (in excel, since I don't know how in SAS) is multiply the N size by the percent that answered each question either a 1,2,3,4,or 5 to determine what # of people in each group responses a certain way to each question (Sheet 1) and then transposed it to the format I *THINK* SAS will want it in (Sheet 2). It looks something like this

Question_Answer	Response	Group_1	Group_2	Group_3
Q0A1	1	50	200	50
Q0A2	2	100	0	25
Q0A3	3	25	25	50
Q0A4	4	75	25	25
Q0A5	5	50	25	50
Q1A1	1	0	50	25
Q1A2	2	100	50	100
Q1A3	3	100	75	0
Q1A4	4	25	75	25
Q1A5	5	75	25	50

From here I need to get the standard deviation of each question for each group and am at a total loss of how to do that. I'm not sure if I should keep the Question column parsed out the way it is (Question 1 Answer 1, Question 1 Answer 2) or just repeat Question1 for five rows and let the response column do the heavy lifting. 

Any help would be greatly appreciated! 

---

[maldito]

Yes! 

Group 1 is 300 people, Group 2 is 275, Group 3 is 200. 

So what I essentially want to do is determine the difference between the responses to each of the questions and whether or not the difference is statistically significant. I hope to accomplish this by running the following independent t-tests

Group 1 vs Group 2 

Group 2 vs Group 3

Group 3 vs Group 1

For each of the questions.

Which, of course, requires the standard deviation to do. 

[Reeza]

---

@maldito wrote:

Which, of course, requires the standard deviation to do. 

---

I would have expected a Chi Square test since this is count/frequency data instead of t-tests using standard deviation.You can look at PROC FREQ for that. 

https://stats.idre.ucla.edu/other/mult-pkg/whatstat/