# One-sample t-test

## One-sample t-tests compare an observed mean to a hypothesized value in a given population

The one-sample t-test is used to answer questions about the

For instance, let's say researchers believe that the majority of households in the United States have at least two televisions. They collect a representative sample from the general population and find that on average there are four televisions. This difference of two televisions between what they expected (M = two televisions per household) and what the actual value (M = four televisions per household) may be statistically significant when using a one-sample t-test.

**difference between the expected or hypothesized mean value of a continuous variable and the observed mean value of a continuous variable**. When using a one-sample t-test, researchers hypothesize a mean value they expect a given population will possess. Then, they collect data from that population of interest to see if the observed mean is statistically different from the hypothesized mean.For instance, let's say researchers believe that the majority of households in the United States have at least two televisions. They collect a representative sample from the general population and find that on average there are four televisions. This difference of two televisions between what they expected (M = two televisions per household) and what the actual value (M = four televisions per household) may be statistically significant when using a one-sample t-test.

**The most important part of using a one-sample t-test is to state the hypothesis for the expected mean value in an***a priori*fashion.### The steps for conducting a one-sample t-test in SPSS

1. The data is entered in a between-subjects fashion.

2. Click

3. Drag the cursor over the

4. Click

5. Click on the continuous outcome variable to highlight it.

6. Click on the

7. In the

8. Click

2. Click

**.**__A__nalyze3. Drag the cursor over the

**Co**drop-down menu.__m__pare Means4. Click

**One**.__S__ample T Test5. Click on the continuous outcome variable to highlight it.

6. Click on the

**arrow**button to move the variable into the**box.**__T__est Variable(s):7. In the

**Test**: box, enter the__V__alue**that researchers expect to occur.***a priori*hypothesized mean value8. Click

**OK**.### The steps for interpreting the SPSS output for a one-sample t-test

1. In the

2. In the

If the

If the

**One-Sample Statistics**table, the observed mean and standard deviation are presented.2. In the

**One-Sample Test**table, look under the**Sig. (2-tailed)**column for the*p*-value that is interpreted.If the

*p*-value is**LESS THAN .05**, then the observed mean is significantly different than what researchers hypothesized or expected.If the

*p*-value is**MORE THAN .05**, then the observed mean is**NOT**significant different that what researchers hypothesized or expected.Click on the

**Download Database**and**Download Data Dictionary**buttons for a configured database and data dictionary for a one-sample t-test.## Hire A Statistician - Statistical Consulting for Students

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