stats prob review

Given the probabilities P(A) =0.4 and P(A∪B) =0.6, what is the probability P(B): If A and B are mutually exclusive? If A and B are independent? 

• a) 0.2; 0.4
• b) 0.2; 0.33
• c) 0.33; 0.2
• d) 0.6; 0.33

P(Freshman or Pizza):

• 27/50
• 4/50
• 3/50
• 30/50

P(Pizza ∩ Water) =

• 62/182
• 120/400
• 58/400
• 140/400

The mean of a distribution that is skewed to the left is smaller than the median.

• True
• False

Which of the following is not a way to choose a random sample of 25?

• Assign numbers. Use a random number generator to choose 25
• Put names in a hat, mix them up and choose 25
• Assemble possible participants in a circle around a person who is blindfolded,  spin the person around 3 times and have them point at a person.  Do this 25 times.

Flipping a fair coin in an experiment is a reasonable way to completely randomize in an experiment.

• True
• False

A matched-pair design is a special type of a randomized block design.

• True
• False

Which of the following is most likely skewed to the right?

• Mean = 50 inches  St. Dev. = 5 inches
• Mean = 300 points St. Dev. = 20 points
• Mean = 10 pounds  St. Dev = 4 pounds

Research on eating habits of families in a large city produced the following probabilities if a randomly selected household was asked “How often during the week do you have a vegetarian (meatless) main dish at dinnertime?” What is the probability that a randomly selected household never has a vegetarian main dish at dinnertime?

• 0.65

• 0.35

• 0

• 0.25

A game consists of drawing three cards at random from a deck of 52 playing cards. You win 3 points for each red card that is drawn. It costs 2 points each time you play. For one play of this game, the sample space S for the net number of points you gain (after deducting the cost of play) is

• S = {-2, 1, 4, 7}

• S = {0, 1, 2, 3}

• S = {0, 3, 6, 9}

• S = {-2, 3, 6, 9}