In: Statistics and Probability
Suppose 40% of the registered voters in a country are Republican. If a sample of 815 voters is selected, what is the probability that the sample proportion of Republicans will differ from the population proportion by more than 4%? Round your answer to four decimal places.
Lower = 812(0.4 - 0.04 ) = 815*0.36 = 293.4
Upper = 812(0.4 + 0.04 ) = 815*0.44 = 358.6
The following information has been provided about the population proportions and the sample size:
Population Proportion = | 0.4 |
Sample Size = | 815 |
We need to compute Based on the information provided, the population men of sample proportions and the corresponding standard error are:
Observe that:
which indicates that the assumption for normal approximation for the sampling distribution is met.
Since we need to use a continuity correction, we need to use the factor to adjust the end points of the end points of the probability intervals, so the new limits are:
Now, the following is obtained using normal approximation: