A ping pong ball is drawn at random from an urn consisting of balls numbered 2 through 10.A player wins 5 dollars if the number

Question

2 years ago

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A ping pong ball is drawn at random from an urn consisting of balls numbered 2 through 10.A player wins 5 dollars if the number

on the ball is odd and loses 5 dollars if the number is even. What is the expected value of his winnings? Round to 3 decimal places.
A card is drawn at random from a standard deck of playing cards (no jokers). If it is red, the player wins 1 dollar; if it is not red, the player loses 5 dollars. Find the expected value of the game.
In a class there are 16 students: 2 are 5'6", 3 are 5'8", 3 are 5'10", 4 are 6', and 4 are 6' 2". A student is chosen at random. What is the student's expected height in inches? Round to the nearest tenth of an inch.

Mathematics

2 answers:

enyata [817] · Answer 1 · 2022-03-22T16:25:00+03:00

19.2 inchesㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤ

ㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤ

maxonik [38] · Answer 2 · 2022-03-22T17:47:07+03:00

9balls with 5 even number and 4 odd numbers, each has a chance to be drawn equally so 1/9, exp = +5*1/9 (ball3)+5*1/9(ball5)…-5*1/9(ball2)-5*1/9( ball4)… = sum of all wining * odd probability + sum of all losing * even probability: 5*4/9+(-5)*5/9, which is - 5/9 dollars or -0.556 dollars. (Should be really called expected value of his losing s)