Proportion- Represents a part of a whole. It can be expressed as fraction, decimal or percentage. 12% =0.12 = 12/100 or 3/25. Proportions can also represent probabilities.

          Symbols used in proportion Notation
                        p = symbol for the population proportion
                        p(hat)= symbol for the sample proportion

p(hat) = x/n                   and                         q(hat) = n-x/n or 1 - p
Where   x= number of sample units that posses the characteristics of interest
             n= sample size


To construct a confidence interval about a proportion, one must use the maximum error of estimate, which is

E= Za/2 x square root of p (hat) q(hat)/n.
Confidence intervals about proportions must meet the criteria that np > 5 and nq >.



J. Santillan