In MS Excel, we can easily test statistical significance by using the function TTEST. Let's first understand the parameters of this function.

## Ttest function syntax

**=TTEST(array1, array2, tails, type)**

**Array1** (Required): Range for dataset 1

**Array2** (Required): Range for dataset 2

**Tails** (Required): This determines if it is a one-tail T-test or two tail T-test.

- 1: One tail T-test
- 2: Two tail T test

**Type** (required): Type of t-test

- 1: Paired T-test, i.e. if the two data sets are related to each other
- 2: Unpaired T-test, the two samples have equal variance
- 3: Unpaired T-test , the two samples have unequal variance

## Ttest formula example

1. Consider the following dataset for T-test.

2. Select the two –datasets in array 1 and array 2.

3. On an Empty Cell, write the formula to perform 1-tail Paired T test

One-tailed probability obtained

4. Similarly, perform a two–tailed paired T test

Two-tailed probability obtained

Based on the obtained value you can accept or reject the null hypothesis. If the T-test gives the probability less than 0.05, then reject the null hypothesis. This means there is less than 5% probability that the null hypothesis is true.

Here, in both cases, p-value> 0.05. So, we accept the null hypothesis.

### Errors

- #NUM! – If the arguments for tail or type are not correct. Tail argument must be 1 or 2. Type argument must be 1,2 or 3.
- #N/A! – The datasets are of different length
- #VALUE – The tail-argument or the type argument are non-numeric

Further reading: How to run f test in Excel