Chp 5 Quiz STA 2023 McGraw Hill

According to the Department of Transportation, 27% of domestic flights were delayed in 2007 at JFK airport. Five flights are randomly selected at JFK. What is the probability that all five flights are delayed?

0.0014 For a binomial random variable X, the probability of x successes in n Bernoulli trials is calculated as formula16.mml Calculate P(X = 5). The Excel's function BINOM.DIST can be used.

Studies have shown that bats can consume an average of 10 mosquitoes per minute. What is the probability that a bat consumes four mosquitoes in a 30-second interval?

0.1755 For a Poisson random variable X, the probability of x successes over a given interval of time or space is calculated as formula19.mmlthe mean number of successes; e ≈ 2.718. Calculate P(X = 4). Time interval is important. The Excel's function POISSON.DIST can be used.

A bank manager estimates that an average of two customers enter the tellers' queue every five minutes. Assume that the number of customers that enter the tellers' queue is Poisson distributed. What is the probability that exactly three customers enter the queue in a randomly selected five-minute period?

0.1804 For a Poisson random variable X, the probability of x successes over a given interval of time or space is calculated as formula19.mmlthe mean number of successes; e ≈ 2.718. The Excel's function POISSON.DIST can be used.

Given the information in the accompanying table, calculate the correlation coefficient between the returns on Stocks A and B. Stock A Stock B E(RA ) = μA = 8.4% E(RB ) = μB = 6.5% σA = 11.80% σB = 7.29% Cov(RA,RB ) = σAB = 16.70%

0.194 The correlation coefficient between the returns RA and RB is calculated as formula15.mml

According to the Mortgage Bankers Association, 8% of U.S. mortgages were delinquent in 2011. A delinquent mortgage is one that has missed at least one payment but has not yet gone to foreclosure. A random sample of eight mortgages was selected. What is the probability that exactly one of these mortgages is delinquent?

0.3570 For a binomial random variable X, the probability of x successes in n Bernoulli trials is calculated as formula16.mml Calculate P(X = 1). The Excel's function BINOM.DIST can be used.

A bank manager estimates that an average of two customers enters the tellers' queue every five minutes. Assume that the number of customers that enters the tellers' queue is Poisson distributed. What is the probability that fewer than two customers enter the queue in a randomly selected five-minute period?

0.4060 For a Poisson random variable X, the probability of x successes over a given interval of time or space is calculated as formula19.mmlthe mean number of successes; e ≈ 2.718. P(X < 2) = P(X = 0) + P(X = 1). The Excel's function POISSON.DIST can be used.

According to a Department of Labor report, the city of Detroit had a 20% unemployment rate in May of 2011. Eight working-age residents were chosen at random. What is the probability that at least two of the residents were unemployed?

0.4967 For a binomial random variable X, the probability of x successes in n Bernoulli trials is calculated asformula16.mml P(X ≥ 2) = 1 - (P(X = 0) + P(X = 1)). The Excel's function BINOM.DIST can be used.

The following table shows the number of students who did not attend statistics class over the 30 class meetings last semester. Number of students Frequency 0 4 1 7 2 9 3 5 4 5 What is the probability that there will be more than one student absent in class today?

0.63 The probability distribution of a discrete random variable is a list of the values with the associated probabilities. Calculate P(X > 1).

The number of cars sold by a car salesperson during each of the last 25 weeks is the following: Number Sold Frequency 0 10 1 10 2 5 What is the standard deviation of the number of cars sold by the salesperson during a week?

0.75 The standard deviation of the discrete random variable X is calculated as formula9.mml The variance of the discrete random variable X is calculated as Var(X) = σ2 = ∑(xi - μ)2 P(X = xi).

For a particular clothing store, a marketing firm finds that 16% of $10-off coupons delivered by mail are redeemed. Suppose six customers are randomly selected and are mailed $10-off coupons. What is the probability that no more than one of the customers redeems the coupon?

0.7528 For a binomial random variable X, the probability of x successes in n Bernoulli trials is calculated asformula16.mml The Excel's function BINOM.DIST can be used.

The number of cars sold by a car salesperson during each of the last 25 weeks is the following: Number Sold Frequency 0 10 1 10 2 5 What is the expected number of cars sold by the salesperson during a week?

0.8 The expected value of X is calculated as E(X) = μ = ∑xi P(X = xi).

The number of cars sold by a car salesperson during each of the last 25 weeks is the following: Number Sold Frequency 0 10 1 10 2 5 What is the expected number of cars sold by the salesperson during a week?

0.8 The expected value of X is calculated as E(X) = μ = ∑xi P(X = xi).

According to a study by the Centers for Disease Control and Prevention, about 33% of U.S. births are Caesarean deliveries. Suppose seven expectant mothers are randomly selected. What is the probability that at least one of the expectant mothers will have a Caesarean delivery?

0.9394 For a binomial random variable X, the probability of x successes in n Bernoulli trials is calculated as formula16.mml P(X ≥ 1) = 1 - P(X = 0). The Excel's function BINOM.DIST can be used.

The foreclosure crisis has been particularly devastating in housing markets in much of the south and west United States, but even when analysis is restricted to relatively strong housing markets the numbers are staggering. For example, in 2011 an average of three residential properties were auctioned off each weekday in the city of Boston, up from an average of one per week in 2005. What is the probability that at least one foreclosure auction occurred in Boston on a randomly selected weekday of 2011?

0.9502 For a Poisson random variable X, the probability of x successes over a given interval of time or space is calculated as 2formula19.mmlthe mean number of successes; e ≈ 2.718. P(X ≥ 1) = 1 - P(X = 0). The Excel's function POISSON.DIST can be used.

Consider the following probability distribution. xi P(X = xi) -2 0.2 -1 0.1 0 0.3 1 0.4 The standard deviation is ____.

1.14 The standard deviation of the discrete random variable X is calculated as formula7.mml The variance of the discrete random variable X is calculated as Var(X) = σ2 = ∑(xi - μ)2 P(X = xi).

The number of homes sold by a realtor during a month has the following probability distribution: Number Sold Probability 0 0.20 1 0.40 2 0.40 What is the expected number of homes sold by the realtor during a month?

1.2 The expected value of X is calculated as E(X) = μ = ∑xi P(X = xi)

An investor owns a portfolio consisting of two mutual funds, A and B, with 35% invested in A. The following table lists the inputs for these funds. Measure Fund A Fund B Expected Value 10 5 Variance 98 26 Covariance 22 The standard deviation for the portfolio return is ____.

5.74% The standard deviation of the portfolio is formula14.mml The portfolio variance is calculated as formula12.mml

A probability distribution of a continuous random variable X gives the probability that X takes on a particular value x, P(X = x).

False If X is a continuous random variable, then P(X = x) = 0 for any value x.

A Bernoulli process consists of a series of n independent and identical trials of an experiment such that in each trial there are three possible outcomes and the probabilities of each outcome remain the same.

False A Bernoulli process consists of a series of n independent and identical trials of an experiment such that in each trial there are only two possible outcomes (success and failure), and in each trial the probability of a success (and failure) remains the same.

Which of the following statements is the most accurate about a binomial random variable?

It counts the number of successes in a given number of trials.

Which of the following is true about the hypergeometric distribution?

The trials are not independent and the probability of success may change from trial to trial.

Testing whether the computer is infected or not would be best described using binomial probability distribution.

True A binomial random variable is defined as the number of successes achieved in the n trials of a Bernoully process.

The number of syntactic errors found in a program code would best be described using a Poisson probability distribution.

True The random experiment satisfies a Poisson process if the number of successes within a specified time or space interval equals any integer between zero and infinity.