Thread: degrees of freedom and critical value

need some help figuring out some simple stats, ive been given the mean and standard deviation for 2 different samples and im having trouble finding the degrees of freedom and critical value in order to do a 2 sample T interval test
Sample A
n=15
SD=5
mean=42
Sample B
n=15
SD=2
mean=44

how do i find the degrees of freedom and critical value? my book says "use technology to find..." but i cant seem to figure it out

thanks!

On a TI-84 Plus scientific calculator the command is invT(.5(1+c),v) where c is the confidence level, and v is the degree of freedom. The degree of freedom (v) is n-1. invT is located in the DISTR menu on the calculator.