Which one of these variables is a binomial random variable?

1. You observe the gender of the next 300 babies born at a local hospital. The random variable represents the number of girls.

2. You roll a die 650 times. The random variable represents the number that appears on each roll of the die.

3. You spin a number wheel hat has 17 numbers 250 times. The random variable represents the winning numbers on each spin of the wheel.

4. You test four pain relievers The random variable represents the pain reliever that is most effective.

5. Testing a pain reliever using 840 people to determine if it is effective. The random variable represents the number of people who find the pain reliever to be effective