# Chapter 4 - Probability - 4-2 Basic Concepts of Probability - Basic Skills and Concepts - Page 145: 12

Unlikely, not unusual.

#### Work Step by Step

We know that $probability=\frac{number \ of \ good \ outcomes}{number\ of\ all\ outcomes}$. The probability of having a girl is $\frac{1}{2}$, therefore in 400 births, the number of girls should be approximately 200. Of course, there are many opportunities around 200, therefore it is unlikely to have exactly 197 girls. On the other hand, it is not unusual because it is quite close to 200.

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.