Statistics

[fran008]

Can anyone kindly explain to me when you use the following tests?

t-test
two tailed t test
chi square.

I am very confused and all the internet sources i looked up confused me even more.

tnx

[GreenDog]

Use t-test to determine whether there is a difference between two arrays of numbers. For example the length of male cat tails VS. female cat tails.
Always use the two tailed t-test.
Use chi square in two cases:
1. Independency - to determine if two parameters are dependant of each other. For example sex and baldness, and you have to decide based on your data if men are tend to baldness more than women.
2. Hypothesis checking - to see how far your data is from your hypothesis. For example to check if the segregation you have is Mendelian.