A doctor is studying heights of newborn babies. The doctor uses 20 inches as a reference point. Babies in the study receive a score to show how close they are to 20 inches.

Question

A baby that is 21 inches long receives a score of +1.

A baby that is 18 inches long receives a score of
.

Answer 1

To calculate the score for a baby that is 18 inches long relative to the reference point of 20 inches, we can use the following method:

1. The reference height is 20 inches.
2. If a baby is 21 inches long, the score is +1, which indicates that the baby is 1 inch longer than the reference height (20 inches).
3. Conversely, if a baby is 18 inches long, they are 2 inches shorter than the reference height.

To compute the score for the 18-inch baby:

\[ \text{Score} = \text{Height} - \text{Reference Height} = 18 - 20 = -2 \]

Therefore, the score for a baby that is 18 inches long is -2.