The above sample size calculator provides you with the recommended number of samples required to detect a difference between two proportions. Sample Size Calculation for Comparing Proportions. Note: A reference to this formula can be found in the following paper (pages 3-4 section 3.1 Test for Equality). for a power of 80%, β is 0.2 and the critical value is 0.84) and p 1 and p 2 are the expected sample proportions of the two groups. ![]() for a confidence level of 95%, α is 0.05 and the critical value is 1.96), Z β is the critical value of the Normal distribution at β (e.g. Where Z α/2 is the critical value of the Normal distribution at α/2 (e.g. ![]() This calculator uses the following formula for the sample size n: In this case you would need to compare 248 customers who have received the promotional material and 248 who have not to detect a difference of this size (given a 95% confidence level and 80% power). ![]() Currently 15% of customers buy this product and you would like to see uptake increase to 25% in order for the promotion to be cost effective. Before implementing a new marketing promotion for a product stocked in a supermarket, you would like to ensure that the promotion results in a significant increase in the number of customers who buy the product.
0 Comments
Leave a Reply. |