Comments on: ANOVA in R https://www.datanovia.com/en/lessons/anova-in-r/ Data Mining and Statistics for Decision Support Tue, 11 Apr 2023 06:22:00 +0000 hourly 1 https://wordpress.org/?v=6.8.2 By: Abbas https://www.datanovia.com/en/lessons/anova-in-r/#comment-28707 Tue, 11 Apr 2023 06:22:00 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-28707 Thank you so much for providing very easy-to-follow stats in R

]]> By: Muhammad Arqam Waheed https://www.datanovia.com/en/lessons/anova-in-r/#comment-22691 Thu, 24 Mar 2022 01:09:15 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-22691 Dear Alboukadel Kassambara,
I have a question, as we do Levene test when the assumption of normality doesn’t meet but in two way ANOVA the normality assumption is getting met in your results, if am not wrong you should have done the Bartlett test and according to the Bartlett p-value comes 0.02 which means it’s violating the assumption of homogeneity but Levene shows 0.06 value which means it meets the assumption, I’m a little bit confused why did you use Levene instead of Bartlett please clarify it.
Thanks

]]> By: Yo https://www.datanovia.com/en/lessons/anova-in-r/#comment-22617 Wed, 02 Mar 2022 18:53:50 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-22617 Do we not need to check if the data is balanced?

]]> By: nb https://www.datanovia.com/en/lessons/anova-in-r/#comment-22608 Fri, 25 Feb 2022 13:32:38 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-22608 Can anyone explain why I get this error message when I run emmeans-test ;
Error in contrast.emmGrid(res.emmeans, by = grouping.vars, method = method, : Nonconforming number of contrast coefficients

]]> By: Guadalupe Rivera https://www.datanovia.com/en/lessons/anova-in-r/#comment-22575 Fri, 11 Feb 2022 18:58:38 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-22575 Hello,
Everything worked so fine until the end with the final plot. The simple bxp is the same as showed but when I add the:

The simple bxp plots males first then female but after adding the stat_pvalue_manual() and labs() is inverted and pvalue lines are misplaced.

]]> By: Lino https://www.datanovia.com/en/lessons/anova-in-r/#comment-22488 Thu, 23 Dec 2021 13:03:10 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-22488 Hi, thanks for a very helpful article. I have a question.

When I run the code for three-way anova, the simple-simple main effects with this script:
treatment.effect %
group_by(gender, risk) %>%
anova_test(pain_score ~ treatment, error = model)
treatment.effect %>% filter(gender == “male”)

It always shows this error notification
Error: Input must be a vector, not a object.

Do you know how to fix it?

]]> By: Sundy https://www.datanovia.com/en/lessons/anova-in-r/#comment-21989 Wed, 12 May 2021 15:05:33 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-21989 Hi, thanks for the example. I am trying a 3-way anova. But experiencing with the codes.
This command is gicving me an error, and this not able to generate the anova table

treatment.effect %
group_by(gender, risk) %>%
anova_test(pain_score ~ treatment, error = model)
treatment.effect %>% filter(gender == “male”)

Error: Input must be a vector, not a object.

Backtrace:
1. treatment.effect %>% filter(gender == “male”)
11. vctrs:::stop_scalar_type(…)
12. vctrs:::stop_vctrs(msg, “vctrs_error_scalar_type”, actual = x)

Does anyone know how I can fix that?

Thks

]]> By: Lindsay https://www.datanovia.com/en/lessons/anova-in-r/#comment-21837 Thu, 01 Apr 2021 13:49:01 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-21837 Thank you for your detailed descriptions. I have a question about how to switch the comparisons. For example, in the two-way ANOVA example, how would you write the model to compare gender at each education_level? Instead of comparing education_level of each gender as in the example.

]]> By: Johanna L. B. https://www.datanovia.com/en/lessons/anova-in-r/#comment-21726 Fri, 26 Feb 2021 08:07:13 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-21726 Dear Mr. Kassambara,

thank you so much for this amazing tutorial! It is the best I ever worked through, made so many things much clearer for me now and really helped me out with my thesis about animal movement data.

Kind regards

]]> By: Gaetan AULLO-RASSER https://www.datanovia.com/en/lessons/anova-in-r/#comment-21608 Thu, 21 Jan 2021 18:35:38 +0000 https://www.datanovia.com/en/?post_type=dt_lessons&p=10872#comment-21608 Dear Alboukadel Kassambara,
Thanks a lot for your great job, this tutorial about ANOVA is the best i ever seen, and i can’t stop using your R packages.

I have a question for you or anybody in this kind community : In my data set, i’m doing a 3-way anova, and then pairwise comparison, with bonferroni correction. My concern is about the N chosen by the algorithm to compute the correction. I have a lot of subset (4x3x5), and even if my df is about 100 rows, I think that my pwc (and so my bonferroni correction) should be computed only in each subset (about 5 rows) indepandantly. PWC are OK because of the use of the “group_by” function, but the BF corr. use the overall N instead of the N of the subset (leading to adjusted p-values divided by 100 in spite of 4-5). Am i wrong in my interpretation of the bonferroni correction ? If the idea seems right, does anybody have an idea on how to resolve that ? (i mean, not strictly manually dividing myself all p-values, recreating p.signif symbols, etc).
Thanks a lot to everybody !
Gaetan.

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