Question

The fasting blood glucose (FBG) levels of a population of women is thought to have a standard deviation of 0.75 mmol/l. A study is being designed to determine whether FBG levels are increased in women who have taken oral contraceptive for at least 6 months. How large a sample is required to detect 0.50 mmol/l if alpha = 0.05 and the power is 0.95?

Answer 1

Step 1:

Effect Size is given by:

                               (1)

Step 2:

Sample Size n is given by:

                                   (2)

Given:

= 0.05

So,

Z = 1.960                                                       (3)

= 95 %

So,

Z_0.95 = 1.645                                                   (4)

Substituting (1), (3) & (4), equation (2) becomes:

So,

Answer is:

29