1. A shipment of 50 mechanical devices consists of 42 good ones and eight defective. An inspector selects five devices at random without replacement. What is the probability that at most four are good? Hint: Use the compliment rule when solving this problem to make it a lot easier.
2. Suppose that the number of times a high school student says "like" in a sentence is approximately normally distributed with a mean of 4 and a standard deviation of .5.
a. What percentage of high schoolers say "like" in a sentence more than 5 times?
b. For high schoolers, what is the 86th percentile for the number of times that "like" is said in a sentence?
3. Suppose that 60% of employees at a particular corporation participate in the optional retirement plan. If a random sample of 50 employees is selected, what is the probability that at least 25 employees in the sample will participate in the optional retirement plan? (Use the normal distribution as an approximation and make the continuity correction.