Hi there! I am trying to work on a university paper and I am having a hard time with the stats part.

I have asked some participants (29) to complete several tasks, and I have the results for the people that successfully completed it, and those who didn't.
I have a breakdown by age (4 groups) and I am trying to prove (Ho) ***that age is independent for the successful completion of the task.***

I am trying to understand whether I have to use chi square or ANOVA. I used anova and I was able to reject the Ho but if I use Chi Square, I fail to reject.

Can someone guide me on this, please?

Thanks in advance, I appreciate it
Pablo

Good afternoon!

ANOVA requires a continuous response variable and is used to determine whether there are any statistically significant differences between the means of two or more independent groups. The chi-square test for independence determines whether there is an association between categorical variables. Your data are entirely categorical, since age is broken down into four categories and the response is binary categorical (complete vs. incomplete). As such, you want to use a chi-square test for independence.

I do not know how rigorously your research paper will be reviewed, nor do I know to what extent your paper will be inspected for proper statistical methods. However, I will offer some guidelines to follow when conducting a chi-square test for independence:

1) The sampling method is simple random sampling (SRS). In other words, you randomly selected your subjects from a population. The population can be people falling within your overall age range.

2) The expected frequency count for each cell of your table is at least 1. Usually this number is 5, but you only have 29 test subjects. If an expected count is a little bit less than 1, that is OK, but try to adhere to the guideline as best you can. If you cannot adhere to this guideline, perhaps you want to mention it in your paper since it could explain conclusions that you were not expecting.

Best of luck!
-Andy