I've used an externally validated, 17-item self-efficacy scale at pre/post an intervention. Answers range from 1 to 5 on a Likert scale. To analyze the different between pre/post, I've been told to combine all 17 items into one item and then do a t-test (or rank sums since ordinal?).
My question is what is meant here by "combine" and how do I go about doing this in SAS?
data looks like this:
Survey id pre/post item1 item2 item3 .......... item 17
1 pre 4 3 3 4
1 post 5 5 4 5
2 pre 3 4 5 3
2 post 4 4 5 4
***
20 pre 3 4 5 4
20 post 5 5 5 5
Very neat.
For all I know from my short experience in industry so far:
1. There is a disconnect between Industry and Academia
2. There is a disconnect between Business & Technology
3. There is a disconnect between Business & process
Overall, it appears the show is run by sales, only sales and more sales, everything else is compliance.
@novinosrin wrote:
Very neat.
For all I know from my short experience in industry so far:
1. There is a disconnect between Industry and Academia
2. There is a disconnect between Business & Technology
3. There is a disconnect between Business & process
Overall, it appears the show is run by sales, only sales and more sales, everything else is compliance.
1. Yes
2. Depends on org
3. Depends on org
Unfortunately, in my experience it takes a really good data science/analytics manager to manage these relationships and have the correct skill set to cross all three of these areas. Not many people have the ability to cross all three.
I went back to the email and had gotten the explanation wrong. They said "add the 17 items into 1 scale and compare the mean total scores between the pre and posttest." So it looks like I should sum up the items and compare means. Does this mean I create a new "sum" variable? Thanks.
Great, thanks. Do I use the SUM function? Do i have to use a class statement?
I'm trying to sum (item1, item2, item3...item17) but it doesn't appear to be the right thing to do.
If I want to do a paired t-test but my data (including new summed items variable) is organized like above (with pre=1, post=2), do i need to create new variables for a pre_sum_item and post_sum item?
so that I can do something like this?:
proc ttest data=response sides=2 alpha=0.05 h0=0; title "Paired sample t-test example"; paired pre_sum_item * post_sum_item; run;
if so, how? Thanks very much for you time!
Registration is open! SAS is returning to Vegas for an AI and analytics experience like no other! Whether you're an executive, manager, end user or SAS partner, SAS Innovate is designed for everyone on your team. Register for just $495 by 12/31/2023.
If you are interested in speaking, there is still time to submit a session idea. More details are posted on the website.
Learn the difference between classical and Bayesian statistical approaches and see a few PROC examples to perform Bayesian analysis in this video.
Find more tutorials on the SAS Users YouTube channel.