Hello,
It's been a while since my A-level statistics course so I just want to make sure I'm doing the appropriate test for my data. I'm a PhD student working in X-ray crystallography.
My situation is that I have 2 populations of data, of varying sizes, in one population the samples have been subjected to a specific treatment and in the other they have not (control group). I want to be able to show that the mean values of various statistics produced from my data processing software are as good in the test group as they are in the control.
I've performed a two tailed unpaired student’s t test, assuming normal distribution and equal variance. The t-values I got were lower than the critical t-value from the tables at 0.05 so I accepted the null hypothesis that the means are the same. From my understanding this means I can accept with a 95% confidence interval that the means between the 2 populations are statistically similar.
Where I'm getting a little unsure is with the confidence interval because obviously the critical t-value gets higher when going from 0.05 to 0.0001 so obviously my t-value is still going to be lower. Does this mean I can assume a 99.99% confidence interval that my means are the same?
Any help and advice would be greatly appreciated.
Thanks,
Sam
It's been a while since my A-level statistics course so I just want to make sure I'm doing the appropriate test for my data. I'm a PhD student working in X-ray crystallography.
My situation is that I have 2 populations of data, of varying sizes, in one population the samples have been subjected to a specific treatment and in the other they have not (control group). I want to be able to show that the mean values of various statistics produced from my data processing software are as good in the test group as they are in the control.
I've performed a two tailed unpaired student’s t test, assuming normal distribution and equal variance. The t-values I got were lower than the critical t-value from the tables at 0.05 so I accepted the null hypothesis that the means are the same. From my understanding this means I can accept with a 95% confidence interval that the means between the 2 populations are statistically similar.
Where I'm getting a little unsure is with the confidence interval because obviously the critical t-value gets higher when going from 0.05 to 0.0001 so obviously my t-value is still going to be lower. Does this mean I can assume a 99.99% confidence interval that my means are the same?
Any help and advice would be greatly appreciated.
Thanks,
Sam