Null-hypothesis for a Independent-Sample t-test

Conceptual Explanation

With hypothesis testing we are setting up a null-hypothesis

With hypothesis testing we are setting up a null-hypothesis – the probability that there is no effect or relationship –

With hypothesis testing we are setting up a null-hypothesis – the probability that there is no effect or relationship – and then we collect evidence that leads us to either accept or reject that null hypothesis.

As you may recall, an independent-sample t-test attempts to compare an independent sample with another independent sample.

Here is a template for writing a independent sample t-test null hypothesis.

There is no significant difference in [insert the Dependent Variable] between [insert Level 1 of the Independent Variable] and [insert Level 2 of the Independent Variable]

Example #1

Let’s say we want to know if teenagers who eat asparagus (sample size = 30) get better ACT scores than teenagers who eat broccoli (sample size = 25) .

Here is the hypothesis:

Here is the hypothesis:

There is a significant difference in ACT scores between students who eat

asparagus and those who eat broccoli.

Here is the null hypothesis:

There is No significant difference in ACT scores between students who eat

asparagus and those who eat broccoli.

Example #2

Let’s say we want to know if IQ scores of teenagers listening to elevator music on their iPods and teenagers who listen to screaming rock.

Here is the hypothesis:

Here is the hypothesis:

There IS a statistical difference in IQ scores between teenagers who listen to elevator music on their iPods and those who listen to screaming

rock.

Here is the null-hypothesis:

There IS NO statistical difference in IQ scores between teenagers who listen to elevator music on their iPods and those who listen to screaming

rock.

Here is the Template Again

There is no significant difference in [insert the Dependent Variable] between [insert Level 1 of the Independent Variable] and [insert Level 2 of the Independent Variable]