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    Chi square on a huge dataset

    I have a situation where I want to look if a simulation gives expected values, so I think a chi squared is the way to do this. Some of the expected probabilities are quite tiny, but others are very large. After doing a chi square I noticed it gives a huge value = 867551.351! I see online that...
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    Question about the normality assumption

    I see everywhere reference to the normality assumption. e.g. for a t-test, you read "data must be approximately normally distributed". When reading more, you see for repeated measure t-test we want the difference to approximately be normal, and for independent we want values in each group to be...
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    Chance performance in a binary response task

    Hello, I am confused by something and wonder if someone can help. With a task of 100 trials that are either TRUE or FALSE, where 80 are TRUE, what is the chance performance if a subject can respond "Yes" or "No"? Is this determined by the number of response options, or by the ratio of...
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    False discovery and multiple test

    I'm reading about the familywise error rate here and trying to put it into perspective. According to this, we calculate FWER = 1 - (1 - alpha)^n. In their example n=10, and with alpha .05, they say this gives 40.1% chance of a type 1 error. Is this practically saying that if i run a study and...
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    Power and T1

    People say that low power due to low sample size makes it more likely to miss a true effect (i.e. Type 2 error). But low sample size results in higher variability. This means e.g. with a t-test, one of our groups could be larger simply due to this variability, but nevertheless be significant. So...
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    Variability instead of means?

    Hello, I was thinking about analysing variability instead of means but could not find much for an answer. I am interested in learning more about this so I would appreciate some feedback. I made some R code to demonstrate my question (I can't code well in R, improvements are much welcome too)...
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    Within-Subjects ANOVA with low sample

    Hello, I have some data that I want to analyse. It is 2x2 within-subjects design. My DV is continuous and the two factors have 2 categorical levels. But I only have 8 subjects, so I am unsure about how to proceed. Is it correct that there is no reasonable alternative to just using an ANOVA? If...
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    3 way ANOVA following it up

    This is quite simple question but im more simple :p I have DV and 3 IVs, each 2 levs. Making up example, lets say they are: DV=performance%, IV1=trial type (seeing, hearing) IV2=item type (target, distractor) IV3=confidence (high, low) Subjected to a 2x2x2 RM ANOVA in SPSS and i see no 3 way...
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    formula for factorial ANOVA interaction effect

    Good day. I have a question regarding the formula for calculating interaction effects. In Andy Field book he gives: SSa×b = SSmodel − SSa − SSb, where a and b are the different factors in our model. What happens when we have 3 or more factors? Is this then: SSa×b×c = SSmodel - SSa - SSb - SSc...
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    Good day

    Hi talkstats memebers! I am Alex. I study Psychology and I want to learn as much as I can about statistics.
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    p values, alpha, and errors

    I was speaking with a classmate about subject heading for this thread and it made me a bit confused. Here are my thoughts: the way I explain p value: probability of observing effect when, in reality, there is no effect. This translates to probability of data given the null (null=there is no...