Horn lengths of texas longhorn cattle are normally distributed. the mean horn spread is 60 inches with a standard deviation of 4.5 inches. calculate the range of horn lengths for the middle 99.7% of texas longhorn cattle. a. 51 in.–60 in. b. 51 in.–69 in. c. 60 in.–73.5 in. d. 46.5 in.–73.5 in.

The empirical rule says that roughly 99.7% of the population is within 3 standard deviations of the mean.

Start at the center 60 which is the mean. Add on 3 standard deviations

60 + 3*4.5 = 73.5

and subtract off 3 standard deviations from the mean

60 - 3*4.5 = 46.5

So roughly 99.7% of the population of cattle has horn lengths between 46.5 inches and 73.5 inches