Dear All,
I have a question regarding calculation of sample size
for t-tests.
Now for doing the above the formula I have is like
this,
N = 2 * [s(x1-x2)]^2 * (1-r) * [z(1 - a/2) + z(1 -
b)]^2/(m1-m2)^2
where,
s(x1-x2) : Estimated std of difference of means;
r : correlation coefficient between x1 and x2;
z(t) : Lower t% pt of normal distribution;
a : Type 1 error;
b : Type 2 error;
m1 : Mean of x1;
m2 : Mean of x2;
I have come across a calculator in website which
requires only the following parameters :
1. Type 1 error;
2. Type II error or power;
3. Estimated Standard Deviation of differences;
4. Minimum detectable difference (m1-m2);
Could anybody provide me with the formula used to
calculate the sample size in such a situation?
Thanks in advance,
Regards,
Indrajit Sen Gupta
Business Analyst
Mu Sigma Business Solutions Pvt Ltd
#21/1-1, Nawab Towers
Cunningham Road
Bangalore 560 052, India
Tel: +91 80 5123 2551
Fax: +91 80 5123 8853
Mob: +91 98807 54816
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www.mu-sigma.com
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