T.TEST FunctionWayne Becker20151018T22:50:08+00:00
The T.TEST function returns the probability associated with the Student’s T Test, which is commonly used for identifying whether two data sets are likely to have come from the same two underlying populations with the same mean.
 This function was introduced in Excel 2010 and so is not available in earlier versions.
 The T.TEST function replaces the TTEST function included in earlier versions of Excel.
Syntax
=T.TEST(array1,array2,tails,type)
Arguments
Argument 
Description 
array1 
The first data set 
array2 
The second data set – must have the same length as array1 
tails 
The number of tails for the distribution. This can be either:

1 
– 
Uses the onetailed distribution 

2 
– 
Uses the twotailed distribution 

type 
An integer that represents the type of ttest. This can be either:

1 
– 
Paired TTest 

2 
– 
Twosample equal variance TTest 

3 
– 
Twosample unequal variance TTest 

Examples

A 
B 
C 
D 
1 
Data 1 
Data 2 


2 
12 
15 


3 
17 
18 


4 
14 
27 


5 
13 
16 


6 
5 
28 


7 




8 
Formula 
Result 
Notes 
9 
=T.TEST(A2:A6,B2,B6,1,1) 
0.053977 
Probability associated with a Student’s paired tTest, with a onetailed distribution 
10 
=T.TEST(A2:A6,B2,B6,2,1) 
0.107954 
Probability associated with a Student’s paired tTest, with a twotailed distribution 
Common Function Error(s)
Problem 
What went wrong 
#VALUE! 
Occurs if either the tails argument or the type argument is nonnumeric 
#NUM! 
Occurs if either:

• 
the supplied tails argument has any value other than 1 or 2 

• 
the supplied type argument is not equal to 1, 2 or 3 

#N/A 
Occurs if the two supplied arrays have different lengths 