Final answer:
The nurse can conclude that the child's growth is within normal limits based on their height and weight falling in the 20th percentile on the growth chart.
Step-by-step explanation:
Based on the information provided, the nurse can interpret the data by recognizing that the child's growth is within normal limits. The fact that the child's height and weight are in the 20th percentile on the growth chart from the National Center for Health Statistics indicates that the child falls within the expected range for their age group. It is important to note that growth charts are not specific to any particular race or ethnicity, but rather provide a general guideline for growth.