Chapter 3: Probability (Add and Mult) Jonathan Hill Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 87 people in the 18-21 age bracket and finds that 74 of them respond and 13 refuse to respond. When 273 people in the 22-29 age bracket are contacted, 251 respond and 22 refuse to Question 1 1/1 pt 9 2 98 respond. Assume that 1 of the 360 people is randomly selected. Find the probability of getting someone in the 22-29 age bracket or someone who does not respond. Giving a test to a group of students, the grades and gender are summarized below Report the answer as a percent rounded to one decimal place accuracy. You need not enter the "%" symbol. A B C Total Male 2 3 11 16 P(22-29 or does not respond) = % Female 12 10 13 35 Total 14 13 24 51 (Hint: It might be helpful to organize the data into a table first.) Question Help: Message instructor If one student is chosen at random, Find the probability that the student was NOT a female that got a "A" . Question 4 0/1 pt '5 3 2 99 39 51 A jar contains 10 red marbles numbered 1 to 10 and 12 blue marbles numbered 1 to 12. A marble is drawn at random from the jar. Find the probability of the given event, please show your answers as reduced fractions. Question Help: Message instructor (a) The marble is red. P(red)= Question 2 1/1 pt 9 2 99 (b) The marble is odd-numbered. P(odd)= Giving a test to a group of students, the grades and gender are summarized below A B C Total (c) The marble is red or odd-numbered. P(red or odd) = Male 10 18 32 Female 6 15 7 28 Total 10 25 25 60 (d) The marble is blue or even-numbered. P(blue or even) = Question Help: Message instructor If one student is chosen at random, . Question 5 0/1 pt 9 3 99 Find the probability that the student was female AND got a "B". Events A and B are indpendent events. Find the indicated Probability. P(A) = 0.3 Question Help: Video Message instructor P(B) = 0.8 Question 3 0/1 pt 9 3 99 P(A and B) = Question Help: Video Message instructorEvents A and B are independent. Find the indicated Probability. P(A) = 0.8 P = [:1 P(A and B) = 016 Question Help: 8 Message instructor 0 Question 7 E 0/1 pt '0 3 Z 99 A hacker is trying to guess someone's password. 'I11e hacker knows (somehow) that the password is 5 digits long, and that each digit could be a number between 0 and 4. Assume that the hacker makes random guesses. What is the probability that the hacker guesses the password on his first try? Please report the answer to four decimal places. Probability = Question Help: 8 Message instructor 0 Question 8 B 0/1 pt 0 3 8 99 Suppose that 80% of students in a college have a smart phone. If you select three students at random, what is the probability that all three have a smart phone? Give your answer as a decimal (to at least 3 places) or fraction Question Help: 8 Message instructor 0 Question 9 E 0/1 pt '0 3 8 99 In a large population, 71% of the people have been vaccinated. If 5 people are randomly selected, what is the probability that at least one of them has been vaccinated? Give your answer as a decimal to 4 places, Question Help: 3 Message instructor 0 Question 10 80/1 pt '0 3 Z 99 In a large population, 64% of the people have been vaccinated. if 4 people are randomly selected, what is the probability that at least one of them has been vaccinated? Round your answer to three decimal places. [: Question Help: 2 Message instructor 0 Question 11 E 0/1 pt '0 3 3 99 Every cereal box has a gift inside, but you cannot tell. from the outside what the gift is, The store manager assures you that 14 of the 44 boxes on the shelf have the secret decoder ring, The other 30 boxes on the shelf have a different gift inside, If you randomly select two boxes of cereal from the shelf to purchase, what is the probability that BOTH of them have the secret decoder ring? (Give answer as a decimal correct to at least three decimal places.) probability = Question Help: a Message instructor 0 Question 12 E 0/1 pt '0 3 :3 99 A bag contains 8 red marbles, 5 white marblesy and 6 blue marbles. You draw 4 marbles out at random, without replacement, Find the following probabilities and round to 4 decimal places. a. The probability that all the marbles are red is b The probability that none of the marbles are red is Question Help: 8 Message instructor 0 Question 13 B 0/1 pt '0 3 3 99 Carlos has a bag of marbles with '4' blue marbles, '4' white marbles, and '6' red marbles. Find the following probabilities of Carlos drawing the given marbles from the bag if the first marble(s) is(are) not returned to the bag after they are drawn. (Give your answer as a reduced fraction) a) A Blue, then a red = [:] b) A red, then a white = [j c) A Blue, then a Blue, then a Blue = C]