# Search results

1. ### testing heteroscedastcity when you can not graph the results

Hi Noetsi. I also think that the residuals do not look heteroskedastic. So the white test claim the same? "And the results were highly significant " of the regression model? The residual doesn't distribute normally but it is probably close enough, so probably shouldn't be a problem. The...
2. ### Sample Size for Variable Data

Hi, You need to have a hypothesis to calculate power, for example, the average size is 45cm and you want to verify it wasn't change by more than 0.2mm for any direction (2 tailed), then you choose sample size that will have the power to identify this change. if for example, if the new average...
3. ### Multicollinearity in regression

Hi Shachar, I don't fully understand what you did, maybe show a simple example? Or the results. "What difference does it make if I "built" it?" I will give you an example: With multicollinearity, the problem is not to predict y, but to know the coefficients, Let's say that X1 and X2 have a...
4. ### Use multiple T-Test vs Anova

Thanks Noetsi :) The post hoc is Tukey HSD. (As Noesti wrote, this for your initial question, I assume not for your example data)
5. ### Multicollinearity in regression

Hi Shachar, How did you compute the variable from several items 1-6 and from items 1,2,4,6? When you say insignificant with only one of the 2 variables, what was the p-value? (The power of the regression with medium effect (0.15) is low (0.25) The difference between the significant model with...

Great :)
7. ### Use multiple T-Test vs Anova

Hi Mrclavet, I tried to run your example over the expected cure numbers (if I understand it correctly.) Total cured / total = 230/242=0.950413223 Group Observed Expected 1 60 58.92561983 2 22 27.56198347 3 20 19.95867769 4 15 14.25619835 5 11 10.45454545 6...
8. ### Use multiple T-Test vs Anova

One way anova compare the means of all the groups. H0 will says all means are equal. But you have binary variables. May be you can run Chi squared goodness of fit expected equal probability for each dog
9. ### Test priori power - Welch T test

Hi, I forgot to update that the R function was fixed. I I tested it successfully. Thanks you Claus :)
10. ### testing heteroscedastcity when you can not graph the results

Ps as a bad workaround you can draw a chart based on random sample data from the 5400..
11. ### testing heteroscedastcity when you can not graph the results

Did you try the white test?( It is a nice one running regression when the residuals (squared) are the DVs and Y and Y squared are the IVs)
12. ### Need help understanding P/T/F coeffs for simple/multiple linear regression, as well as ANOVA, VIF, etc

Hi S, You run the T-test for each coefficient, to check if the IV really help you to predict the DV (Y). While the F test is for the entire model, comparing the model with all the IVs to the model without the IVs: (Y=b) You need p-value to be small since this is the probability to reject a...
13. ### Regression Diagnostics

The qq-plot looks very nice (not normal). Doesn't look like random outliers...
14. ### Looking for help getting a higher R squared value.

I think the same, but may be Blanco is doing something wrong, so it is better to see the data.

16. ### Regression

Glad to help :) I fixed to IV (The IVs are preferable to be continuous....)
17. ### Regression

Hi, First, when having ordinal DV with 8 values you probably will get reasonable results also with the linear regression. (the recommended is still the ordinal logistic regression) (https://www.statisticalanalysisconsulting.com/how-to-analyze-likert-type-dependent-variables/) I assume the...
18. ### Hypothesis test, how do I calculate the mean from my observations?

Hi lonestartiger First, no need to be embarrassed, asking questions is the goal of the forum .., Is it daily treatment? every day before and after the treatment? Or is it one-time treatment? Can you please be more specific, what are the minutes and what is the score? What test do you plan...
19. ### ranking based on numbers

Wilcoxon signed rank /Man Whitney U are tests to "compare" populations using samples (or the same population in different condition) . But this is not what you try to do. You can try for example ranking based on the order: Sort all values <Q1 low, between Q1 and Q3 - intermediate >Q3 high (Q2...
20. ### Dependent vs. Independent Variables?

What do you think?