- Thread starter Sophia Craig
- Start date

Oneway analysis of variance with a post-hoc test seems logical.

With kind regards

Karabiner

With kind regards

Karabiner

Thank you so much for your reply!

Just want to make sure i understand, the reasoning behind choosing these methods is:

1) I will choose one way ANOVA since i only have 1 independent variable (even though it has 3 levels)

2) i will go for ANOVA first because i need to identify whether or not the means of my 3 groups differ

So i will have a null hypothesis: All group means are the same, then when i reject my null hypothesis i go for post hoc

3) i will go for a post-hoc test to identify which mean is different?

-Is there a specific post-hoc test i should go for?

-Also, the question does not ask for the difference in mean average, i just assumed that ANOVA would be the best?

Also, the goal of my test is to find out which drug had the least negative effect on reaction time (the data in the above table is reaction time measured in seconds)

So how would the Dunnett's post hoc test help me identify the Drug?

So how would the Dunnett's post hoc test help me identify the Drug?

1) 1-way ANOVA table. This shows that there is at least one contrast between the three drugs that is statistically significant.

2) Multiple comparisons using Bonferroni post-hoc test. This shows that Drug A is statistically different from both Drug B and Drug C.

Drug B is statistically different from Drug A, but NOT from Drug C/Placebo. Drug C/Placebo is statistically different from Drug A, but NOT from Drug B.

There is a lot more information in the screen shots, but this is the more relevant information to your questions.

Most of these charts just provide summary statistics of the three drugs. The key elements are:

1) 1-way ANOVA table. This shows that there is at least one contrast between the three drugs that is statistically significant.

View attachment 4292

2) Multiple comparisons using Bonferroni post-hoc test. This shows that Drug A is statistically different from both Drug B and Drug C.

Drug B is statistically different from Drug A, but NOT from Drug C/Placebo. Drug C/Placebo is statistically different from Drug A, but NOT from Drug B.

View attachment 4293

There is a lot more information in the screen shots, but this is the more relevant information to your questions.

1) 1-way ANOVA table. This shows that there is at least one contrast between the three drugs that is statistically significant.

View attachment 4292

2) Multiple comparisons using Bonferroni post-hoc test. This shows that Drug A is statistically different from both Drug B and Drug C.

Drug B is statistically different from Drug A, but NOT from Drug C/Placebo. Drug C/Placebo is statistically different from Drug A, but NOT from Drug B.

View attachment 4293

There is a lot more information in the screen shots, but this is the more relevant information to your questions.

Thank you for taking your time to go through all of this. I am still finding this a bit difficult to understand. Does this mean that Drug B still has the most detrimental effect on the reaction time?

And is the bonferroni the right post hoc test to use to help me identify the drug? Or should i use something else?

For the graph 1, how were you able to identify that not all drugs had the same mean? Was it the degrees of freedom or F value?

Standard Deviation is a measure of the variation in the sample

N = sample size

This is the Bonferroni post-hoc test that I explained above.

4) Does this mean i have to use post hoc?

View attachment 4297

View attachment 4297