Binomial probabilities

Answer Key - Grade 11 Math Worksheet - Challenge Me

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

1. 1.

   Milo makes each free throw with chance 0.6 and shoots 5. To the nearest thousandth, what is the chance of at least 4 makes?

   0.337
2. 2.

   Each of Ren's 8 bulbs passes the check with chance 0.9, on its own. To the nearest thousandth, what is the chance of at least 7 bulbs passing?

   0.813
3. 3.

   A binomial count needs a fixed number of tries, two outcomes, and the same chance each time. Which situation of Tala's fits a binomial distribution?

   • Tala shoots 10 free throws, each made with chance 0.7; X counts the makes
   • Tala picks 3 cards at random from 10 cards, 4 red, without putting any back; X counts the red cards
   • Tala rolls a fair number cube once; X is the number it shows
   • Tala tosses a fair coin until it lands heads; X counts the tosses
4. 4.

   A binomial count needs a fixed number of tries, two outcomes, and the same chance each time. Which situation of Zee's fits a binomial distribution?

   • Zee guesses on 8 quiz questions, each with 4 choices; X counts the right guesses
   • Zee spins a spinner until it lands on red; X counts the spins
   • Zee measures the heights of 8 plants; X is the tallest height
   • Zee takes 2 pens at random from a cup of 6, 2 blue, without putting them back; X counts the blue pens
5. 5.

   A binomial count needs a fixed number of tries, two outcomes, and the same chance each time. Which situation of Bo's fits a binomial distribution?

   • Bo picks 4 names at random from a list of 12, 5 from one class, with no name picked twice; X counts that class's names
   • Bo counts the leaves on one plant; X is that count
   • Bo plants 12 seeds, each sprouting with chance 0.8 on its own; X counts the sprouts
   • Bo plants seeds one by one until one sprouts; X counts the seeds planted
6. 6.

   A binomial count needs a fixed number of tries, two outcomes, and the same chance each time. Which situation of Esme's fits a binomial distribution?

   • Esme tosses a fair coin 20 times; X counts the heads
   • Esme picks 5 cubes at random from a bag of 10, 3 green, without putting any back; X counts the green cubes
   • Esme times one walk to school; X is the minutes
   • Esme tosses a fair coin until 2 heads in a row land; X counts the tosses
7. 7.

   Each try is counted (0.3) or not (0.7). Jun makes each free throw with chance 0.3. What is the fewest shots for a chance of at least 0.9 of getting at least 1 make?

   7
8. 8.

   Each try is counted (0.2) or not (0.8). Each seed in Kira's old seed packet sprouts with chance 0.2. What is the fewest seeds for a chance of at least 0.95 of getting at least 1 sprout?

   14
9. 9.

   Each try is counted (0.1) or not (0.9). Each of Luz's long bean-bag throws lands in the basket with chance 0.1. What is the fewest throws for a chance of at least 0.5 of getting at least 1 hit?

   7
10. 10.

    Each try is counted (0.4) or not (0.6). Each of Milo's paper airplanes lands in the hoop with chance 0.4. What is the fewest throws for a chance of at least 0.99 of getting at least 1 landing?

    10