Probability Of Sample Proportion Formula. Sample Size n N Z2 p 1-pe2 N 1 Z2 p 1-pe2. So we want the probability that the z -score is greater than or equal to 167.
For example say that a statistical study claims that 038 or 38 of all the students taking the ACT test would like math help. It turns out that the mean and standard deviation of the sample proportion are related to the population proportion in the following way. There is roughly a 95 chance that p-hat falls in the interval 05 07 for samples of this size.
First we should check our conditions for the sampling distribution of the sample proportion.
P p p. Feb 21 2011 When Sal was mentioning the 68-95-997 rule in a prior video the first two numbers were actually rounded to the nearest whole number. The variance of Y sigma2_Y is by definition the expected value of the squared difference of Y. The probability is approximately 095 that p-hat falls within 2 standard deviations of the mean that is between 06 2 005 and 06 2 005.
