Make Sure You Have Your Dependent Variable and Factor Selected Now Left Click on Options

The Options Menu Comes Up Left click the Boxes to check-off What you want Descriptive Stats Homogeneity of Variance Test Means Plot Then left click continue

Why the Crud Would I Pick Those Tests? Your ANOVA appears to say that the fly ash addition does not change pavement durability – yet your field people say otherwise. The data for a valid ANOVA test meets the assumptions of ANOVA One of the assumptions is that the variance of each different treatment is the same (or nearly so). You picked descriptive statistics which will tell you the standard deviation of each treatment You also picked a test called the homogeneity of variance test which will check to see whether differences in variances are large enough to indicate a problem Finally you ask the computer to show you the means of each treatment.

Now You Have Set Your Options, Just Click Ok like before to run your test

Out Comes the Data – This Time With Extras

The Descriptive Stats Show You The Standard Deviation of Each Treatment These standard deviations are suppose to be About the same. Are they?

Here is Your Homogeneity of Variance Test The null hypothesis is that all variances are the same Rejecting the null hypothesis means you believe they are different Your test statistic was 243.298 – What are the chances of getting a more far out Value than that? What does that tell you about your alpha level if you reject the null hypothesis?

Heres’ the Plot of the Means As you move from 1 (no fly ash) to 5 (100% fly ash) does it Look like anything is Happening to the Strength?

But What Does the ANOVA Test Say? The null hypothesis is that fly ash addition does not change the pavement Strength Rejecting the null hypothesis would mean that it does. What is our alpha level if we reject the null hypothesis?

Our

Our Descriptive Statistics Let Us Look at the 95% confidence interval for strength of each type of concrete Does any type of Concrete stand out from The crowd to where The confidence Intervals do not Overlap? Do you have any idea Why the ANOVA test Does not reject the Null hypothesis?

But is the Test Valid?