Suppose the scores of a standardized test are normally distributed. If the population standard deviation is 4 points, what minimum sample size is needed to be 95% confident that the sample mean is within 1 point of the true population mean? z0.10, 1.282 : z0.05, 1.645 : z0.02, 51.960 : z0.01, 2.326 : z0.005, 2.576
Use the table above for the z-score, and be sure to round up to the nearest integer.