7/22/2019 Stats Probability Cheat Sheat Exam 2

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If A and B are mutually exclusive events with P(A) = 0.70, then P(B)can be any value between 0 and 1.can be any value between 0 and 0.70.cannot be larger than 0.30.None of the above statements are true.

If A and B are independent events with P(A) = 0.20 and P(B) = 0.60, then P(A|B) is0.2000

In the notation below, X is the random variable, c is a constant, and V refers to thevariance. Which of the following laws of variance is not correct?V(c) = 0V(X + c) = V(X)V(X + c) = V(X) + cV(cX) = c2 V(X)

Which of the following statements is always correct?P(A and B) = P(A) * P(B)P(A or B) = P(A) + P(B)P(A or B) = P(A) + P(B) + P(A and B)

P ( )C

A = 1- P(A)

An experiment consists of tossing an unbiased coin three times. Drawing a probabilitytree for this experiment will show that the number of simple events in this experiment is8

Use the following information to answer questions 6 and 7: The weights of newbornchildren in the United States vary according to a normal distribution with mean 7.5pounds and standard deviation 1.25 pounds. The government classifies a newborn ashaving low birth weight if the weight is less than 5.5 pounds.

What proportion of babies weigh less than 5.5 pounds at birth?0.0548

If the government wanted to change the value 5.5 pounds to a weight where only 2% ofnewborns weigh less than the new value, what weight should they use?

4.9375 pounds

If you are given a table of joint probabilities of two events, any probability computed byadding across rows or down columns is also calledmarginal probabilityjoint probabilityconditional probabilityBayes theorem

The effect of increasing the standard deviation of a normally distributed random variableis that the distribution becomesnarrower and more peaked.flatter and wider.

If the random variable X follows a Uniform distribution with a=7.5 and b=11.5, what isP(X-0.13) = 1-0.4483 = 0.5517

What is P(0.29

7/22/2019 Stats Probability Cheat Sheat Exam 2

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If X and Y are random variables with E(X) = 5 and E(Y) = 8, then E(2X + 3Y) is:40131834

A function or rule that assigns a numerical value to each simple event of an experiment iscalled:a sample space.a probability tree.a probability distribution.a random variable

If X is a binomial random variable with n = 25, and p = 0.25, then the variance andstandard deviation of X are 6.25 and 2.5, respectively.TrueFalse

The number of customers arriving at a department store in a 5-minute period has aPoisson distribution.TrueFalse

CH6 REC WS- Assume that the weights of bags of potato chips are independent of oneanother. Assume that the third quartile is 19 oz. Suppose I randomly select 4 bags ofchips. P(W>18)=1/4, P(W 18) = P(1st > 18) P(2st > 18) P(3st > 18) P(4st > 18)

What is the probability that none of the 4 bags weigh more than 18 oz?P(NONE>18) + P(ALL < 18) = P(1 st < 18) P(2st < 18) P(3st < 18) P(4st < 18)

What is the probability that at least one of the 4 bags weighs more than 18 oz?P(At least 1 bag > 18) = 1 P(NONE>18) = 1 ()4

CH61) A random experiment is an action or process that leads to one of several possible

outcomes2) A sample space of a random experiment is a list of all possible outcome of the

experiment. The outcomes must me exhaustive (all possible outcomes must beincluded) and mutually exclusive (no two outcomes can occur at the same time).3) Requirements of probabilities: Given a sample space S={O1,O2,,Ok}, the

probabilities assigned to the outcomes must satisfy two requirements:a. The probability of any outcome must lie between 0 and one 0