Home Test for One ProportionTo test for the difference between the sample proportion and a specific user-defined value. Test for One MeanTests for a difference between a sample mean and a user specified value. Test for Two ProportionsTo test for the difference between two sample proportions. Test for Two MeansTests for the difference between the means of two samples. Confidence Interval For One ProportionTo obtain a sufficient number of subjects with a specific attribute. It is estimated using proportion and precision.
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Wemedoo Sample Size and Power Calculator

Below we have provided a free sample size and power calculator for all to use. This calculator performs five of the most frequently used calculations and is provided as is without warranty. If you require additional calculations or professional biostatistical services please contact us and we will be more than happy to help you.

Confidence Interval For One Proportion

Result

CONFIDENCE INTERVAL FOR ONE PROPORTION

Purpose: To obtain a sufficient number of subjects with a specific attribute. It is estimated using proportion and precision.

Example: Population studies reveal that 20% of participants are smokers. How many subjects is necessary in a subsequent study to detect 20% smokers with a precision of 3% (from 17% to 23%) using a confidence interval (CI) of 95%.

Design:
Confidence Interval = 0.95
Proportion = 0.20
Precision = 0.03

Result: Assuming that the proportion of smokers in the population is 20%, a sample of 683 subjects is sufficient to produce a 95% confidence interval that between 17% and 23% (true population proportion) of the subjects within the sample will be smokers.

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