STATS EXAM 2

=13/160

=13/160 An inspection on 160 parts made from two production lines at a factory yields the following table. A part is randomly selected from these 160 parts. The probability that this part is defective is about

99%

If every else remain the same which of the following confidence level will result the widest confidence interval?

=1-norm.dist(-0.50,0,1,true)

Let Z be the standard normal random variable. Find P(Z>−0.50)

=1-binom.dist(425,500,0.60,true)

A city government asks 500 randomly selected people whether or not they are employed. The population percentage of employment is 0.60. Which of the following shows the correct EXCEL formula to calculate the probability that at least 426 of these people are employed?

Ux¯ = 10, Ox¯ = 0.6/sqrt(36)

A manufacturer claims that the mean weight of its ice cream cartons is 10ounces with a standard deviation of 0.6 ounce. Assuming 36 cartons are selected. Let x¯ represent the mean sales price of the sample. Find the mean and standard deviation of x¯, i.e., Ux¯ and Ox¯:

=confidence.norm(0.05,9,50)

A physician wanted to estimate the mean length of time that a patient had to wait to see him after arriving at the office. A physician wanted to estimate the mean length of time that a patient had to wait to see him after arriving at the office. A random sample of 50 patients showed a mean waiting time of 30 minutes and a standard deviation of 9 minutes. Which of the following calculates the margin of error (EBM) for the 95% confidence interval for the mean waiting time?

Distribution B

A random variable X has a normal distribution. The distributions shown below are the distributions of the sample averages of X (i.e. x̄). One of the distributions is for the averages of a sample of size 30 (n = 30), and the other distribution is for the averages of samples of size 60 (n = 60). Which distribution is for the sample of size 30?

p' = 150/750; q' = 600/750; ebp = 0.035

A survey in a community states that 150 out of 750 people smoke on a regular basis. Using the information from this survey, a researcher wishes to estimate the required sample size. He wants to be 99% confident and wants the sample proportion to be within 3.5% of the population proportion. Which of the following is correct?

p' = 250/750; q' = 500/750; ebp = 0.015

A survey in a community states that 250 out of 750 people smoke on a regular basis. Using the information from this survey, a researcher wishes to estimate the required sample size. He wants to be 87% confident and wants the sample proportion to be within 1.5% of the population proportion. Which of the following is correct?

p' = 480/1200; q' = 1 - 480/1200; ebp = 0.025

A survey in a community states that 480 out of 1200 people smoke on a regular basis. Using the information from this survey, a researcher wishes to estimate the required sample size. He wants to be 80% confident and wants the sample proportion to be within 2.5% of the population proportion. Which of the following is correct?

=confidence.norm(0.05/2,55000,13200,150)

A survey is conducted to estimate the average household income in a large metropolitan area. A random sample of 150 households in this area yielded an average household income of $55,000 with a standard deviation of $13,200. Which of the following calculates the margin of error (EBM) for the 95% confidence interval for the mean household income in this area?

One can be 80​% confident that the mean​ drive-through service time of this​ fast-food chain is between 165.8 seconds and 175.7 seconds.

A trade magazine routinely checks the​ drive-through service times of​ fast-food restaurants. An 80​% confidence interval that results from examining 789 customers in one​ fast-food chain's​ drive-through has a lower bound of 165.8 seconds and an upper bound of 175.7 seconds. What does this​ mean?

=binom.dist(5,20,0.10,false)

A woman buys 20 one-dollar lottery tickets per month. The probability of any ticket being a winning ticket is 0.10 or 10%. Which of the following shows the correct EXCEL formula to compute the probability that in any one month, exactly 5 of the tickets that the woman buys are winning tickets?

=binom.dist(9,15,0.52,false)

According to Harris Interactive poll, 52% of American college graduates have Facebook accounts. Suppose this result is true for the current population of American graduates. Which of the following shows the correct EXCEL formula for the probability that exactly 9 American college graduates in a sample of 15 have Facebook accounts is about:

=(13+90-8)/160

An inspection of 160 parts made from two production lines at a factory yields the following table. A part is randomly selected from these 160 parts. The probability that this part is defective and is made from production line 2 is about

=147/160

An inspection of 160 parts made from two production lines at a factory yields the following table. A part is randomly selected from these 160 parts. The probability that this part is good is about

=norm.inv(0.33,132000,13500)

Annual salaries of senior chemical engineers are normally distributed with a mean of $132,000 and a standard deviation of $13,500. Which of the following shows the correct EXCEL formula to calculate the 33rd percentile for salaries of senior chemical engineers?

=1-norm.dist(109,100,12,true)

Assume that children's IQs (Age 6-12) follow a normal distribution with mean 100 and standard deviation of 12. Find the probability that a randomly selected child has IQ above 109.

=1-binom.dist(0,5,0.10,true)

At a marketing company, past record shows that 10% of all cold calls result in a sale. A salesman will make five cold calls tomorrow. Which of the following shows the correct EXCEL formula to find the probability that he will make at least one sale from these calls tomorrow?

=0*0.125 + 1*0.375 + 2*0.375 + 3*0.125

Cora is playing a game that involves flipping three coins at once. Let the random variable X be the number of coins that land showing "heads". Here is the probability distribution for X. Which of the following calculates the expected value of the number of coins that land showing "heads"?

=norm.dist(0.04,0,1,true) - norm.dist(-1.06,0,1,true)

For the standard normal random variable Z, calculate P(−1.06<Z<0.04).

=norm.dist(16000,16890,4220/sqrt(35),true)

Household credit card debt in a certain region has a mean of $16,890 and a standard deviation of $4,220. Calculate the probability that the mean credit card debt of a random sample of 35 households would be $16,000 or less.

85%

If every else remain the same which of the following confidence level will result the narrowest confidence interval?

We can be 95​% confident that the mean length of sentencing for the crime is between 52.7 and 61.3 months.

In a random sample of 32 criminals convicted of a certain​ crime, it was determined that the mean length of sentencing was 57 ​months, with a standard deviation of 12 months. A district attorney calculated the 95​% confidence interval for the mean length of sentencing for this crime and he got 52.7 for the lower bound and 61.3 for the upper bound. Interpret the interval.

Ux = 276.1, Ox = 34.4/sqrt(64)

In a recent year, Washington State public school students taking a mathematics assessment test had a mean score of 276.1 and a standard deviation of 34.4. A random sample of 64 students is drawn form this population. Identifying the mean and standard deviation of the sample mean score.

Computing a 90% confidence interval rather than a 80% confidence interval. / Decreasing the sample size

In a survey of 1000 people, 700 people said that they voted in the last presidential election. Let p denote the proportion of all people who voted. Which of the following actions would result in a confidence interval wider than the 80% confidence interval computed from this sample? Choose ALL that apply.

Computing a 95% confidence interval rather than a 90% confidence interval. / Decreasing the sample size

In a survey of 1000 people, 700 people said that they voted in the last presidential election. Let p denote the proportion of all people who voted. Which of the following actions would result in a confidence interval wider than the 90% confidence interval computed from this sample? Choose ALL that apply.

=700/1000 and =norm.inv(1-0.10/2, 0, 1)

In a survey of 1000 people, 700 people said that they voted in the last presidential election. Let p denote the proportion of all people who voted. Which of the following calculates the point estimate for p and also the critical value for the 90% confidence interval for p?

There is 90​% confidence that the true proportion of worried adults in the population is between 49.8% and 55%.

In a survey of 1002 ​adults, a polling agency​ asked, "When you​ retire, do you think you will have enough money to live comfortably or not?". Of the 1002 surveyed, 525 stated that they were worried about having enough money to live comfortably in retirement. An economist calculated the 90​% confidence interval for the proportion of adults who are worried about having enough money to live comfortably in retirement and he got 0.498 for the lower bound, and 0.550 for the upper bound. Inter

=confidence.t(0.13,2.5,12)

Last Wednesday, a random sample of 12 students was surveyed to find how long it takes to walk from the Fretwell building to the College of Education building. The survey team found a sample mean of 10 minutes with a standard deviation of 2.5 minutes. Assuming walking times from Fretwell to the College of Education are normally distributed, which of the following calculates the margin of error (EBM) for the 87% confidence interval for the population mean of walking times?

=sumproduct(D1:F1,D2:F2)

Michael is a basketball player who regularly shoots sets of 2 free-throws. The table below displays the probability distribution of X , the number of shots that Michael makes in a set of 2 attempts. Which of the following calculates the expected value of the number of shots that Michael makes?

=norm.dist(0.80,70,10)

Scores on the common final exam in the Elementary Statistics course are normally distributed with a mean of 70 and a standard deviation of 10. The department has the rule that in order to receive an A in the course his score must be in the top 20% of all exam scores. Which of the following shows the correct EXCEL formula to calculate the minimum IQ score required by this program?

=binom.dist(0,7,0.05,true)

The Wallace family is going on vacation to Sunny Dunes, where there is only a 5% chance of rain on any given day. Which of the following shows the correct EXCEL formula to compute the probability that they enjoy their 7-day vacation and have no rainy days (i.e. P( X = 0 rain))?

=1-norm.dist(8.125,8.0,0.2,true)

The actual amount of hot water dispensed by a coffee brewer, when it is set to dispense 8.0 ounces, is normally distributed with mean 8.0 ounce and standard deviation 0.2 oz. The probability that a randomly selected nominal 8.0 ounce cup of coffee will be brewed with more than 8.125 ounces is about:

=1-norm.dist(210000,215000,45000/sqrt(60),true)

The average sales price of single-family houses in Mooresville is $215,000 with a standard deviation of $45,000. A random sample of 60 single-family houses in Mooresville is selected. Let x¯ represent the mean sales price of the sample. What is the probability that the sample mean sales price is more than $210,000?

= 0.09 + 0.12 + 0.03 + 0.06

The following two-way contingency table gives the breakdown of the population in a particular locale according to party affiliation (A, B, C, or None) and opinion on a bond issue: A person is selected at random. The probability that the person opposes to the bond issue is

0.280

The following two-way contingency table gives the breakdown of the voters in a particular locale according to gender and political party preference. A person is selected at random from this population. Let A be the event that the selected person will vote for the Republican party; B be the event that the selected person is a Male. Find the probability that the selected person is a Republican and a male.

0.190

The following two-way contingency table gives the breakdown of the voters in a particular locale according to gender and political party preference. A person is selected at random from this population. Let A be the event that the selected person will vote for the Republican party; B be the event that the selected person is a female. Find the probability that the selected person is a Republican and a female.

=(470+480-190)/1000

The following two-way contingency table gives the breakdown of the voters in a particular locale according to gender and political party preference. A person is selected at random from this population. Let A be the event that the selected person will vote for the Republican party; B be the event that the selected person is a female. Find the probability that the selected person is a Republican or a female.

=norm.inv(0.67,1.95,0.2)

The length a wild of lemur's tail has a normal distribution with a mean of 1.95 feet with a standard deviation of 0.2 feet. Which of the following shows the correct EXCEL formula to calculate the 67th percentile of lemur tail length.

=30/250 and =norm.inv(1-0.10/2, 0, 1)

The manager of the dairy section of a large supermarket chose a random sample of 250 egg cartons and found that 30 cartons had at least one broken egg. let � denote the proportion of all cartons which have at least one broken egg. Which of the following calculates the point estimate for p and also the critical value for the 90% confidence interval for p?

=80/550 and =norm.inv(1-0.04/2,0,1)

The manager of the dairy section of a large supermarket chose a random sample of 550 egg cartons and found that 80 cartons had at least one broken egg. let � denote the proportion of all cartons which have at least one broken egg. Which of the following calculates the point estimate for p and also the critical value for the 96% confidence interval for p?

0.90

The proportions of families with various numbers of children age 18 or under in a small town are given in the following table. One family is randomly selected from this town. Find the probability that the selected family has at least 1 children age 18 or under.

0.50

The proportions of families with various numbers of children age 18 or under in a small town are given in the following table. One family is randomly selected from this town. Find the probability that the selected family has at most 1 children age 18 or under.

=35/54

The table shows the results of a survey in which 90 dog owners were asked how much they have spent in the last year for their dog's health care, and whether their dogs were purebred or mixed breeds. Given that a randomly selected dog is purebred, find the probability that the dog owner spent at least $100 on healthcare. (i.e. Among the dogs who are purebred, what's the likelihood that the dog owner spent at least $100)

=35/90

The table shows the results of a survey in which 90 dog owners were asked how much they have spent in the last year for their dog's health care, and whether their dogs were purebred or mixed breeds. Given that a randomly selected dog owner spent at least $100, find the probability that the dog was a Purebred. (i.e. Among the dog owners who spent at least $100, what's the likelihood that the dog was a purebred)

21/40

The table shows the results of a survey in which 90 dog owners were asked how much they have spent in the last year for their dog's health care, and whether their dogs were purebred or mixed breeds. Given that a randomly selected dog owner spent less than $100, find the probability that the dog was a mixed breed. (i.e. Among the dog owners who spent less than $100, what's the likelihood that the dog was a mixed breed)

the mass of a test cylinder of concrete

Which of the following random variables is continuous?

the weight of a baby giraffe

Which of the following random variables is continuous?

the weight of a chicken

Which of the following random variables is continuous? the number of tacos a teenager can eat in one sitting/ the number of quarters in a cash register/ the total rolled on two fair 6-sided dice/ the weight of a chicken

=binom.dist(9,15,0,25,true)

You are taking a multiple-choice quiz that consists of fifteen questions. Each question had four possible answers, only one of which is correct. To complete the quiz, you randomly guess the answer to each question. Which of the following shows the correct EXCEL formula to compute the probability of guessing less than ten answers correctly.

=1-binom.dist(3,5,0.2,true)

You are taking a multiple-choice quiz that consists of five questions. Each question had five possible answers, only one of which is correct. To complete the quiz, you randomly guess the answer to each question. Which of the following shows the correct EXCEL formula to compute the probability of guessing less than four answers correctly.

=1-binom.dist(3,5,0.25,true)

You are taking a multiple-choice quiz that consists of five questions. Each question had four possible answers, only one of which is correct. To complete the quiz, you randomly guess the answer to each question. Which of the following shows the correct EXCEL formula to compute the probability of guessing at least four answers correctly?

=binom.dist(4,20,1/6,true)

You are taking a multiple-choice quiz that consists of twenty questions. Each question had six possible answers, only one of which is correct. To complete the quiz, you randomly guess the answer to each question. Which of the following shows the correct EXCEL formula to compute the probability of guessing less than five answers correctly.