5. Is p-value<0.05?NoDo not reject null
7Example 2. Paired SamplesIs there a difference in the mean preference before and after visiting the Disney theme park? •The difference in these cases is examined by a paired samples t test. To compute t for paired samples, the paired difference variable, denoted by D, is formed and its mean and variance is calculated. 0:0DH(People have the same mean preference before and after visiting Disney park)1:0DH(People have different mean preferences before and after visiting Disney park)20SPSS: Paired-Samples T Test•Analyze => Compare Means => Paired‐Samples T Test•Select paired variables (pref_after and pref_before)21SPSS: Output22Reject the H0of equal means (P value < 0.05)Conclusion:people have different preference after visiting park thanbefore visiting
8Interpreting the results of a paired-samples t testNull hypothesis (H0): the average population value of two variables are the same–If you fail to reject the null hypothesis, then conclude by re-stating the null hypothesis => StopExample: people have the same preference after visiting park as before visiting--If H0is rejected, then the average value is notthe same for the two variables. State which variable is higherExample: people have higherpreference after visiting park than before visiting23Example 3. Two Independent Samples
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- Statistics, Null hypothesis, Statistical hypothesis testing, Statistical tests, Student's t-test