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Statistical Analysis [5-7]
ODS Output
Creating the output data set from Proc ttest is a little different than the other Proc Steps.
You need to use the ODS (Output Delivery System) to create the output data sets.
Let's take a look at the VITAL data set again.
Example
You need to use the ODS (Output Delivery System) to create the output data sets.
Let's take a look at the VITAL data set again.
Example
To create the output data sets, you will have to add an ods statement before Proc TTest:
Example
ODS Output Statistics=Stat;
Proc ttest Data=Vital;
Class Trt;
Var SBP;
Run;
The ODS Output statement tells SAS to create an output data set.
The STATISTICS option tells SAS to create a new data set called STAT that contains the statistics from Proc ttest:
The STAT data set is created:
Beside the STATISTICS option, there are 5 additional output data sets that can be created:
- STATISTICS: Summary Statistics
- CONFLIMITS: Confidence Limits
- EQUALITY: Equality of Variance Test
- EQUIVLIMITS: Confidence Limits for Means
- EQUIVTESTS: Equivalence t tests
- TTESTS: t tests
Example
ODS Output Ttests = tresults;
Proc ttest Data=Vital;
Class Trt;
Var SBP;
Run;
The TRESULTS data set is created containing the t-tests results:
Exercise
Let's take a look at the CAMPAIGN data set again.
Let's take a look at the CAMPAIGN data set again.
Conduct a two-sample t-test and find out if the purchases from one group significantly differ from the other.
Create the following four output data sets:
Create the following four output data sets:
- Summary Statistics
- Confidence Limits
- Equality of Variance
- Ttests results
Need some help?
HINT:
You can list all of the output data sets in one ODS statement.
SOLUTION:
ODS Output
Statistics = Stat
Conflimits = confl
Equality = Equa
Ttests = tresults;
Proc ttest data=campaign;
class group;
var purchase;
run;
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