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. (1 point) Responses 51 in.–60 in. 51 in.–60 in. 51 in.–69 in. 51 in.–69 in. 60 in.–73.5 in. 60 in.–73.5 in. 46.5 in.–73.5 in.

1 answer

To calculate the range of horn lengths for the middle 99.7% of Texas longhorn cattle, we can use the properties of a normal distribution, specifically the empirical rule (or 68-95-99.7 rule).

According to this rule:

  • Approximately 68% of the data lies within one standard deviation of the mean.
  • Approximately 95% of the data lies within two standard deviations of the mean.
  • Approximately 99.7% of the data lies within three standard deviations of the mean.

Given:

  • Mean (μ) = 60 inches
  • Standard deviation (σ) = 4.5 inches

To find the range for the middle 99.7% of horn lengths:

  1. Calculate the lower bound: \[ \text{Lower bound} = \mu - 3\sigma = 60 - 3(4.5) = 60 - 13.5 = 46.5 , \text{inches} \]

  2. Calculate the upper bound: \[ \text{Upper bound} = \mu + 3\sigma = 60 + 3(4.5) = 60 + 13.5 = 73.5 , \text{inches} \]

Therefore, the range of horn lengths for the middle 99.7% of Texas longhorn cattle is 46.5 inches to 73.5 inches.

The correct response is: 46.5 in.–73.5 in.