Question: Stats-R-Us laboratories has conducted a survey to determine how many strawberries are eaten by 100,000 people during a one year period. The data indicate that the number of strawberries eaten is approximately
normally distributed with a mean of 29 strawberries, and a standard deviation of 4 strawberries eaten by each person. According to this data, approximately how many of the surveyed people ate more than 25 strawberries during the course
of the year?
Solution: According to the definition of a normal distribution, two-thirds, or about 68%, of data are within 1 standard deviation of the mean. The mean is 29, with standard deviation of 4, so 68,000 people (68% of
100,000) ate between 25 and 33 strawberries. Because the normal distribution is symmetric around the mean, then 16% of the data points are more than 1 standard deviation. 16% of 100,000 is 16,000, so 16,000 people ate more than 33
strawberries. Using these values, 16,000 + 68,000 = 84,000 people ate more than 25 strawberries, so the answer is E.