Use the normal distribution to approximate the desired probability.
-Find the probability that in 200 tosses of a fair die, we will obtain at least 40 fives.
A) 0.1210
B) 0.3871
C) 0.2229
D) 0.0871

Question

Quizplus · Accepted Answer

The probability of getting a five on a single toss of a fair die is 1/6. The mean of the number of fives in 200 tosses is 200 * 1/6 = 33.33. The standard deviation is sqrt(200 * 1/6 * 5/6) = 4.08. The probability of getting at least 40 fives is the probability of getting a z-score of (40 - 33.33) / 4.08 = 1.64 or more. Using a standard normal distribution table, we find that the probability of getting a z-score of 1.64 or more is 0.1210.

Use the Normal Distribution to Approximate the Desired Probability