Which test to use to compare means for normal and non normal data

#1
Hi!
I have quantitative test scores I wish to compare. However, one group (n=27) is not normally distributed and the other one (n=21) is normal.
Thank you
 

Karabiner

TS Contributor
#2
You can use the t-test (Welch test). With n(total)=48, we can expect that the
mean difference is normally distributed in the population (see central limit theorem).

With kind regards

Karabiner
 
#4
I am not sure what you mean by your first question. However, see the histogram and other descriptive statistics. Thanks so much for your help!
I am looking up the Welch test. I don't recall learning about that!
 

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hlsmith

Not a robit
#5
Well, what I was alluding to was that scores can be percentages, which are bound between 0 and 1.00. If all of the scores were high (e.g. .90's but there was quite a bit of variability, your standard deviation may not represent the data coverage symmetrically. Say your mean = 95% and std = 10%.

But your data seem fine.