Total sample size required to determine whether a correlation coefficient differs from zero.

Instructions: Enter parameters in the red cells. The answer will appear in blue below.

The standard normal deviate for α = Z_{α} =

The standard normal deviate for β = Z_{β} =

C = 0.5 * ln[(1+r)/(1-r)] =

Total sample size = N = [(Z_{α}+Z_{β})/C]^{2} + 3 =

Reference: Hulley SB, Cummings SR, Browner WS, Grady D, Newman TB. Designing clinical research : an epidemiologic approach. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013. Appendix 6C, page 79.