# Need help with interpretation?

#### PiiNK

##### New Member
I conducted a Three-Way ANOVA and have the output ready, I'm really struggling with the interpretation and need help! Statistics is a subject I really struggle with and what I have been reading has been so confusing, so would really appreciate some help

This is an example of the question: "Summarise the orientation x contrast interaction and use the appropriate descriptive information to support your interpretation". I am told I need to use the mean and mean differences, but how do I do this and where are the mean and mean differences on the output?

Type III Sum of Squares: 710320.658
Df: 1
Mean square: 710320.658
F: 110.154
Sig: .000
Partial eta squared: .655

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#### Buckeye

##### Member
Well, I can tell you that a contrast is a linear combination of parameters in which the coefficients add to 0, Contrasts are often used in multiple comparisons and hypothesis testing. Suppose I have two groups with means mu1 and mu2, respectively. An example contrast might be

H0: (1/3)mu1 = (2/3)mu2

As far as what you wrote, "orientation x contrast interaction" is a confusing phrase, And perhaps I gave you extraneous information because of it. Are orientation and contrast both factors? I think it would be best if you posted the problem in its entirety.

#### PiiNK

##### New Member
Ah sorry! Orientation and Contrast are the independent variables for the study and they've been manipulated together.

Background on the study: The study examined reaction time data on a face recognition task. The first factor was orientation - faces were either presented in an upright orientation or an upside down orientation. Contrast was also manipulated with faces being presented under high and low contrast conditions. Reaction times were recorded for correct recognition of faces (time taken to make an accurate decision about whether they had seen the faces on a previous occasion). Participants completed the task under all conditions. The participants were divided into two groups based on their scores on a self-report index measuring sleep quality (good sleep quality group versus poor sleep quality group.

What is confusing me now is what it means by calculating mean differences? I don't understand if it's a matter of running a compare means test on SPSS or if it's actually subtracting the total mean values from each other (but that seemed so basic so I wasn't sure if it was that!).

I've attached part of my output from a threeway ANOVA...

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