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1. Which analysis do i need?

So the participants are basketball players? Did each participant of the 83 watch the 40 videos? and answered 40 times? What did you try to do? what tests did you think of? Do you have example data?
2. Type of statistical test?

PS, the Likert with 5 doesn't distribute normally, but the requirement is for a residuals' normality. |Any way in your case you use a large sample size (120) so it shouldn't be a problem even if the distribution of the residuals skewed (not symmetrical)
3. Logistic regression: correction for multiple comparisons

So you run 90 separated regressions? and you ask about the overall model significance? (F) Why?
4. question regarding grouping several variables

Hi Stat20, The second model is incorrect ...even if you ignore the interaction X1X2 I will take one row for example: In the first model: X1 X2 X1X2 Y 4 6 24 40 In the second model: X1 X2 X1X2 Y 4 0 0 40 0 6 0 40...
5. What is n in bonferoni test

Correct. What test do you run for each pair? If for example, you use a significant level of 0.05 in each test As the end in each test (pair) you run the allowed probability for type I error is 0.05 but the potential maximum allowed probability in all the test So the probability not to get a...
6. What is n in bonferoni test

Hi Jave, What test do you want to run? How many tests? For example, if you compare 4 algorithms: A, B, C, D: If you run the following tests: A-B (for example t-test to compare A average to B average) A-C A-D B-C B-D C-D In this example case, you run 6 comparisons so n=6.
7. What is n in bonferoni test

Hi Jave, n is the number of tests you perform. I think it is better you use the Sidak Correction (similar but more accurate and a bit more power)
8. Finding Correlations

So you want to group together (1,1,1,2,8) with (1,2,1,3,9) and (4,4,4,4,4) with (3,4,5,4,5)?
9. Finding Correlations

Hi Ewa, First, not all the correlation values in the matrix are necessarily significant ...need to be proved. (but the sample size is large) For example, -0.004 may not be significant. (I didn't test) The method is usually the opposite, first, you think what you want to achieve and then you...
10. Finding Correlations

Hi Ewa, I'm not sure if this is what you after? Following the correlation matrix ( I removed two partial rows)| Y-Design X1-Food X2-menu X3-existing X4-Tech
11. Two way anova and Bonferroni

Thanks Miner, this is a very interesting article! I assume it is relevant for any multiple regression. I guess this is the reason why an automatic process like the stepwise method for multiple regression is good only as a screening method and not as a way to build a model?
12. 95% confidence interval using standard error of a proportion

Hi, I think that the sample size of 50 is small enough to use the binomial distribution instead of any other approximation distribution. Since the distribution is discrete the confidence level won't be exactly the required level. On the other hand, maybe sample size of 50 is big enough to use...
13. Outlier analysis with IQR and different sample size

Okay, so let's think about the theoretical question... Probably doing it separately for each of the 15 distributions will okay. Just an idea, what about multiple regression? (didn't say which one, for linear you need to meet the assumptions and the normality is only for the residuals) Then...
14. Outlier analysis with IQR and different sample size

Hi C, Usually, when n=1000 you won't get df=3, but this was only an example and describe your point it well :) Per my understanding when trying to identify the distribution you won't look only on the hedge but on the entire distribution. Like Shapiro Wilk does for the Normal distribution and...
15. Outlier analysis with IQR and different sample size

Hi, Per my understanding, the goal of "removing outliers" is to remove one of the following: 1. Mistake - leaving this mistake will influence the results. 2. Valid value with a very low probability that got into your small sample, and if you do another 10 similar samples you shoudn't get such...
16. t-test or ANOVA? urgent

I was trying to lead you to the same direction as @Karabiner. I also think you should go for 2 t-tests with Bonferroni correction (actually better use the Sidak correction with is more accurate: α=1−n√(1−α′)
17. t-test or ANOVA? urgent

Hi K, If I understand you correctly... (I hope), it is not repeated ANOVA/paired-t since you don't check the DV twice, but you check 2 different independent DVs Two way ANOVA is one DV with two IVs.(the factors) Two way ANOVA is like Y=f(x1,x2) while as I understand your case is Y1=f(x1) ...
18. t-test or ANOVA? urgent

Hi K, You should always check that your case meets the assumption of the test you use. Do you want to check each question separately? or the average of the questions? What are the combinations that you want to check? Can you please show a simple demo example? If you run two separate t-tests...
19. t-test or ANOVA? urgent

Hi K, I don't understand. So you compare only two groups? So why multiple comparisons? ANOVA with two groups and t-test with equal variances are identical tests (the same p-value)
20. Could someone please help me with this Biostats problem.

Can you please show me how did you get 46, 296? The confidence interval is around the average ...