Basic Probability Worksheet, Intro to Stats

R. Sinn, Fall 2007 Name ________________________

1. ELENA writes the letters of her name on slips of paper and draws one at random. Find the probability of...

(a) drawing an E (b) drawing an L

(c) drawing of vowel (d) not drawing an E

2. A committee is being formed at the United Nations. 1 person will be selected at random for president. If there are 8 people from Japan, 6 from New Zealand, 12 from Russia and 4 from Belarus in the drawing, find the probability of the person...

(a) being from Belarus (b) being from Japan

(c) being from Russia (d) not being from New Zealand

3. A jar contains 3 types of cookies: 9 chocolate, 6 peanut butter and 5 oatmeal raisin. If Joe reaches in a grabs 1 at random, find the probability of...

(a) grabbing a chocolate cookie (b) grabbing a peanut butter cookie

(c) grabbing an oatmeal raisin cookie (d) not grabbing a chocolate cookie

4. Jenny has 14 red balloons, 9 blue balloons and 12 green balloons. If Jenny chooses one balloon at random to give to her friend Eva, find the probability of her giving away...

(a) a red balloon (b) a blue balloon

(c) a green balloon (d) a balloon that is not blue

5. If each letter of the word MISSISSIPPI is written on a card, and one of the cards is drawn at random, find the probability that...

(a) an S is drawn (b) an I is drawn

(c) an I is not drawn (d) a P is drawn

Slightly Less Basic Probability

6. Example 4.2.1 Suppose you roll two dice and add their face values. Find…

(a) P(7) (b) P(2 or 5)

(c) P(6) (d) P(4 or less)

7. Suppose you draw a card from a standard deck of 52. Find…

(a) P(Red) (b) P(Jack)

(c) P(Red or Jack) (d) P(Diamond or Ace)

8. The numbers 1 to 15 are written on ping pong balls and placed in a fish bowl. If one ball is selected at random, find…

(a) P(odd) (b) P(not prime)

(c) P(multiple of 3 OR odd) (d) P(multiple of 3 AND odd)

9. If a family has triplets (and having boys and girls is equally likely), find…

(a) P(no Boys) (b) P(exactly 2 Girls)

(c) P(at least 2 Girls) (d) P(at least 1 Boy)

10. If you flip a (fair!) coin 4 times, find….

(a) P(at least 1 tails) (b) P(no tails)

(c) P(exactly 3 heads) (d) P(2 heads and 2 tails)