turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

Find a Community

- Home
- /
- Analytics
- /
- Stat Procs
- /
- Comparing means between several groups

Topic Options

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Email to a Friend
- Report Inappropriate Content

03-30-2017 04:04 AM

Hello,

**I am tring to understand the results I got.**

My code is:

proc ttest data=sasuser.sasfile010916;

class stage;

format stage firstgroup.;

var ROA1 ROA2 ROA3 ROA4 ROE1 ROE2 ROIC Q LNQ ;

run;

I copmare between the mean of group 1 to the mean of the other 3 groups mean together.

The result I got for the variable ROA1: T value = 0.06 Pr = 0.94 while F value is 2.77 pr<0.0001

According to the t value, I understand that there is not difference between group 1 to the other 3 groups together. But what is the meaning of the F value here?

Thanks for any clue...

Yael

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Email to a Friend
- Report Inappropriate Content

03-30-2017 08:18 AM

It would help if we could see the results.

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Email to a Friend
- Report Inappropriate Content

03-30-2017 10:50 AM

Generally the F test is related to whether your variances are equal. The Ttest is supposed to test if the means differ given that the variances in the two groups are similar. When the variances are not then you maybe shouldn't be using a ttest. A large F value indicates that the variances may not be equal and the p-value is the probabiity they aren't equal given some other assumptions such as normality of the data.