Probability — Test Answers

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Shawn is playing a game with a set of cards. Half of them are blue and the other half are yellow. In the game, the player guesses the color of the top card, looks at the card, and returns the card to the deck. The player continues to do this, shuffling the deck after each guess. Shawn has guessed the first three attempts as "blue” and has been correct on each guess. He says he will guess "yellow” for the next card since a yellow card is due to happen. Is Shawn’s reasoning correct?

A
Yes, half of the cards are yellow, so the fourth card should be yellow to compensate for the first three cards being blue.
B
No, the law of large numbers says that the proportion of yellow cards should approach the true probability after many trials.
C
No, all of the cards have been blue so far, so the next one must also be blue.
D
Yes, Shawn has guessed well so far, so it is clear that he cannot miss.
24

Suppose a day from this city is selected at random. Let event cap A is equal to heavy traffic and event cap b is equal to bad weather. Are events cap A and cap b independent?

A
Yes, cap p times cap A is equal to cap p times open paren cap A divides cap b close paren .
B
No, cap p times cap A is not equal to cap p times open paren cap A divides cap b close paren .
C
No, cap p times cap A is equal to cap p times open paren cap A divides cap b close paren .
D
Yes, cap p times cap A is not equal to cap p times open paren cap A divides cap b close paren .
25

Which of the following is the correct value and interpretation of cap p times open paren cap b divides cap m close paren ?

A
cap p times open paren cap b divides cap m close paren is equal to 0 point 3 6 ; given that the vehicle color is blue, there is a 0 point 3 6 probability that it has been driven many miles.
B
cap p times open paren cap b divides cap m close paren is equal to 0 point 5 4 ; given that the vehicle has been driven many miles, there is a 0 point 5 4 probability that the color is blue.
C
cap p times open paren cap b divides cap m close paren is equal to 0 point 3 6 ; given that the vehicle has been driven many miles, there is a 0 point 3 6 probability that the color is blue.
D
cap p times open paren cap b divides cap m close paren is equal to 0 point 5 4 ; given that the vehicle color is blue, there is a 0 point 5 4 probability that it has been driven many miles.

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