Sample Size Determination
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Two Samples Mean: Hypothesis test
This utility can be used to calculate required sample size when your aim is to test whether two sample means are significantly different.
Formula used and other details
Your guesstimate of first Sample mean (M1)
Required
Approxiate estimate of first Sample mean based on previous studies / pilot studies etc.
Your guesstimate of Standard Deviation of first Sample mean (SD1)
Required
Approxiate estimate of Standard Deviation of sample mean, based on previous studies / pilot studies etc.
Your guesstimate of second Sample mean (M2)
Required
Approxiate estimate of second Sample mean based on previous studies / pilot studies etc.
Your guesstimate of Standard Deviation of second Sample mean (SD2)
Required
Approxiate estimate of Standard Deviation of second sample mean, based on previous studies / pilot studies etc.
Ratio of Sample Size in two Groups (N2 / N1)
Enter number from 0.01 to 9.00
Required
Sample Size in Group 2 / Sample Size in Group 1
Confidence Level %
Enter positive number between 0.01 to 99.99
Required
In percentage. Commonly used values are 95, 99 and 90. Should be between 0.01 to 99.99.
Power ( 1 - β)
Enter positive number between 0.01 and 99.99
Required
In Percentage. Should be between 0.001 to 99.999. Common values are 80 % and 90 %
One sided or two sided
Enter either 1 or 2
Required
One tailed or two tailed hypothesis
Sample Size Required =