What you’ll learn to do: calculate and interpret z-scores and determine standard deviations from the mean

If apples weigh 4 ounces and the standard deviation of the weight of an apple is 1 ounce, what proportion of apples would weigh between 3 ounces and 5 ounces? Assuming the distribution of apple weights are approximately normal, we can use properties of the normal distribution and the empirical rule to help answer this question.