The lengths of a certain species of fish are approximately normally distributed with a given mean mc019-1.jpg and standard deviation mc019-2.jpg. According to the Empirical Rule, what percentage of the fish will have lengths within 1 standard deviation of the mean?
69 cm is one standard deviation below the mean
for a normally distributed (bell curve) population
___ about 68% lie within one standard deviation of the mean ___ 34% above and 34% below
in this case , the 34% below the mean is added to the 50% above the mean (the 1/2 of the population equal to or longer than 79 cm)
so 84% of the population is longer than 69 cm