Final answer:
Approximately 68% of heights in a normal distribution are within 1 standard deviation of the mean.
Step-by-step explanation:
The percentage of heights that are within 1 standard deviation of the mean in a normal distribution is approximately 68%. This is known as the Empirical Rule, which states that for data with a bell-shaped and symmetric distribution, approximately 68% of the data falls within one standard deviation of the mean.