Binomial averages, the Central Limit Theorem and the normal curve

Answer Key - Grade 11 Math Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   Ari makes 70% of free throws and takes 20 shots. On average, how many shots should Ari make?

   14
2. 2.

   80% of bean seeds sprout. Bo plants 50 seeds. On average, how many should sprout?

   40
3. 3.

   Kira flips a fair coin 100 times and counts heads. The count is binomial with n = 100 and p = 0.5. What is the variance of the count?

   25
4. 4.

   Luz guesses on 64 true-false questions. The count is binomial with n = 64 and p = 0.5. What is the variance of the count?

   16
5. 5.

   About 10% of Milo's school's 400 lockers stick. The count is binomial with n = 400 and p = 0.1. What is the variance of the count?

   36
6. 6.

   One in five of 625 seed packets has a bonus seed, Ren reads. The count is binomial with n = 625 and p = 0.2. What is the variance of the count?

   100
7. 7.

   Tala checks a crate of 100 apples; about 10% have a bruise. With n = 100 and p = 0.1, what is the standard deviation of the count?

   3
8. 8.

   Zee's class flips 900 fair coins and counts heads. With n = 900 and p = 0.5, what is the standard deviation of the count?

   15
9. 9.

   Ari rolls 144 number cubes and counts even results. With n = 144 and p = 0.5, what is the standard deviation of the count?

   6
10. 10.

    Bo's club makes 400 kites; one in five gets a long tail. With n = 400 and p = 0.2, what is the standard deviation of the count?

    8