Question

# We are going to study the difference in means of two independent samples. We assume the...

We are going to study the difference in means of two independent samples. We assume the difference in mean between these two samples 6.0 (assuming: mu1=16 and mu2=10), and the standard deviation (among all patients in two groups) is 10. Our hypothesis is H0: mu1 = mu2 vs Ha: mu1 not equal to mu2. To achieve a power of 80% to test the difference of 6.0, how many patients in total should we recruit? The significance level is 0.05, and we assume attrition = 10%

We are going to study the difference in means of two independent samples. We assume the difference in mean between these two samples 6.0 (assuming: mu1=16 and mu2=10), and the standard deviation (among all patients in two groups) is 10. Our hypothesis is H0: mu1 = mu2 vs Ha: mu1 not equal to mu2. To achieve a power of 80% to test the difference of 6.0, how many patients in total should we recruit? The significance level is 0.05, and we assume attrition = 10%

Sample size calculation

For 0.05 level, z = 1.96

d = 6

sd=10

for 80% power, for β =0.20, z = 0.842  = 43.6

The sample size for each group =44

Total sample size for two groups=88

Accounting for 10% attrition, (100/90)*88 =97.78

= 98 ( rounded)

The required sample size = 98

#### Earn Coins

Coins can be redeemed for fabulous gifts.