Question 1: Suppose eight items were selected at random from a production line that is known to

produce 15% defective unites.

(a) What is the probability of selecting exactly two defective units?

(b) What is the probability of selecting exactly zero non-defective units?

(c) What is the probability of selecting less than three non-defective units?

(d) What is the probability of selecting two or more defective units?

Question 2: On average the local sub shop services one customer every 20 minutes. Calculate the

probability that there:

(a) will no customers in the next 4 hours?

(b) will no customers between the hours of noon and 3:00 PM?

(c) will be at least two customers between the hours of 10:00 AM and 2:00 PM?

(d) will no more than three customers in the next 2 hours?

Question 3: From a group of 8 apples and 4 pears, how many fruit basket combinations or size 4

are possible:

(a) with no restrictions?

(b) with 2 apples and 2 pears?

(c) with 1 apple and 3 pears?

(d) with 3 apples and 1 pear?

Question 4: A lot of size 50 contains six non-conforming units. What is the probability that the

sample of five units selected at random without replacement contains:

(a) less than 3 conforming units?

(b) exactly 2 non-conforming units?

(c) at least 2 non-conforming units?

(d) exactly 1 conforming units?

Question 5: Suppose a multiple-choice test was composed of 20 questions, each with four

possible choices (a - d) of which only one is the correct answer. A passing grade requires a

student to answer sixteen or more questions correctly.

(a) What is the probability of a student that guesses blindly will pass the quiz?

(b) What is the probability of selecting less than 3 incorrect answers?

(c) What is the probability of selecting exactly 16 correct answers?

(d) What is the probability passing the test if, on each question, the student can eliminate two

of the selections and then guess between the remaining two selections?