effect size

  1. S

    Meta-analysis: How should one handle non-significant studies containing no raw data?

    Let's say that I'm conducting a meta-analysis, looking at the performance of group A and group B with respect to a certain construct. Now, some of the studies that I'll come across will report that no statistical differences could be found between the two groups but no exact test statistics...
  2. M

    Paired T-test effect size

    Can someone please direct me to a calculation for an effect size for a paired samples t-test along with a reference? Thanks in advance.
  3. K

    Effect sizes and repeated measures

    Hi there, I am doing a bit of research looking at the effects of repeat test taking. Students are allowed to take a test multiple times. I have a dataset including student scores on each iteration of the test. I have done a repeated measures ANOVA to try to determine whether scores...
  4. A

    Post-hoc Power, effect size for Chi-square

    I need help with my post-hoc power analysis, specifically the effect size: I measure children's successrate under four conditions. My dependent variable is nominal (specifically binary, with the values 0 (failed) and 1(succeeded)) My independent variable is nominal with four categories. My...
  5. A

    Graphing Effect Size Comparions

    Hi! I would like to take a single school's achievement data (as an effect size) and plot that on a scatterplot graph with the matched district and state level data as well on the same graph, so as to compare where the school of interest falls as compared to the district and state. What do I...
  6. Z

    Calculating D from interaction F values

    Hi everyone I am reviewing a study where I need to calculate an effect size of gender differences (Cohen's d). The study looks at the effect of effort on men and women, but do not report the standard deviations for me to calculate d, but do report an repeated measures ANOVA value interaction...
  7. A

    Calculating effect size for a within group comparison of score before&after treatment

    Hi all, :wave: I am wondering which formula will be more suitable for calculating effect size (Cohen's d) of an intervention with scores obtained before (1 score) & after treatment (1 score) in the same group of individuals. :confused: As I had two scores, I used paired t-test for for within...
  8. B

    Calculating effect size for generalized linear model?

    Hi, I have carried out a generalized linear model (in SPSS) with one dependent variable and two factors. Both factors have multiple categories (ie. one factor has three 'groups', the other four). I would like to calculate the effect size for each factor. I have found a lot of information...
  9. Y

    Calculation of effect size in Hierarchical regression

    Hello there, I have conducted a hierarchical regression with two steps. Statistical significance resulted form the first step, as the second step did not seem to add any value to the model. How could I calculate the effect size of the model? And more specifically: Suppose that we have...
  10. E

    Standard deviation of the mean difference out of Pre/Post Test Descriptive Statistics

    I have several RCT pre/post intervention studies that I am calculating Hedge's g for. All of the studies report the difference of mean and difference of standard deviation between pre/post for each group except one. I know how to calculate the difference of mean [= Mean(post)-Mean(pre)], but...
  11. P

    Moderated Mediation when Independent Variable is also the moderator

    I have a question on a special case of moderated mediation... I want to compare some effect sizes of: a "simple moderation model" with a "moderated mediation model in which the IV is also a moderator". I don't have data yet. But I want to know if the betas (effect sizes) explained in...
  12. K

    What is the difference between statistical significance (based on probability) and...

    (Questions wouldn't fit) What is the difference between statistical significance (based on probability) and an effect size? I am fairly new to stats and finding a bit of an up hill marathon at the moment. I have been asked to research the question posted above, yet I have exhausted my...
  13. trinker

    Does n Affect Effect Size

    We all know the pvalues are affected by sample size. I've had profs claim that effect size is unaffected by sample size. But I'm thinking this may not be true. Let's take standardized mean difference with the pooled sd in the denominator: where... and where... and also... I'm not...
  14. trinker

    effect size to report or not

    I challenged a prof today and I said that an effect size should not be reported for non significant results. He strongly disagreed. What are your thoughts (I'm ok if I'm wrong but I want to know why). If anyone has specific sources to cite that would be awesome.
  15. K

    Comparing two methods to measure disease severity

    I am testing a new, fast method to score disease severity in an animal model of a human disease. M appears to be less sensitive than the gold standard scoring method, G. G is discrete and has a range (0,1,2...20). M is continuous and varies from 0 to 1. The linear correlation coef between...
  16. P

    Calculating effect size.

    Hi, I'm learning about ANOVA's and understand that to report results I have to calculate effect size. We have been taught to calculate W^2 (Omega squared) first and then carry on with comparison tests. Can you tell me if the W^2 has to be significant before computing comparison tests or is...
  17. A

    effect size for McNemar's?

    Is it possible to calculate effect size for comparisons made using the McNemar's test? If so, how? I am at a total loss on this after spending A LOT of time combing the web. I would be so grateful if anyone had any ideas!
  18. A

    Cohen's d for one-sample/paired-samples vs. independent samples, and pooled SDs

    I have a few questions for you all about Cohen's d and pooled SDs! This is my first post, hope it goes in line with forum guidelines. 1) one-sample / paired-sample vs. independent samples Cohen's d calculation It seems that for calculation of Cohen's d (an estimate of effect size), you...
  19. L

    Eefect size

    Hi.. i have a question on effect size..i get a negative value of effect size..should i report it as an absolute value or a negative value.. and one more thing, if i swapped the means and SD in the effect size calculator,,i get the same value minus the negative sign...how do i determine...
  20. D

    Determining error of a slope based on a dependent variable containing error

    I am currently attempting to compare the slopes of many linear graphs. Each graph is a plot of Time (independent variable) vs. Effect Size (dependent variable). I know the standard error associated with each measure of Effect Size. I want to know the error of the slope of each graph. However...