7 ms·
Can you be more specific on why you think the t-test is invalid when the data is non-normal? Duration data may be non-normal, but given finite visits and a rea
by jimmybot 13y ago
Can you be more specific on why you think the t-test is invalid when the data is non-normal? Duration data may be non-normal, but given finite visits and a reasonable number of visits, sampling for the mean surely is.
- btilly 13y agoYou are right that in the presence of sufficient data, everything converges to the normal and we're fine. However the difference between the t-test and the normal to which it is an approximation is that the t-test takes into account corrections the rate of convergence to the estimated normal. The details of that convergence is dependent upon the distribution of individual samples, and the t-test is predicated on the assumption that each and every sample is from a normal distribution.