Final Bana

Question 1 The SAT scores have an average of 1200 with a standard deviation of 60. A sample of 36 scores is selected. What is the probability that the sample mean will be larger than 1224? Round your answer to three decimal places.

.008 60/squareroot(36)=10 1224-1220=24 24/10=2.4 1-norm.s.dist(2.4,1)

General Hospital has noted that they admit an average of 8 patients per hour. What is the probability that during the next two hours exactly 8 patients will be admitted? (Round your answer to three decimal places.)

.012 POISSON.DIST(8,16,0)

General Hospital has noted that they admit an average of 8 patients per hour. What is the probability that during the next hour less then 3 patients will be admitted? (Round your answer to three decimal places.)

.014 POISSON.DIST(2,8,1)

Many people who bought X-Game gaming systems over the holidays have complained that the systems they purchased were defective. In a sample of 1200 units sold, 18 units were defective. Determine the upper limit for the 95% confidence interval for the population proportion. Round your answer to three decimals

.023

Question 2 Refer to Question 1, what is the p-value associated with the hypothesis test? Round your answer to three decimal places.

.024 =NORM.S.DIST(-2,1)

Consider Question 4, what is the probability that these 64 students spent a combined total of more than $715.21? Enter your answer as a decimal and not as a percent and round your answer to 3 decimal places.

.031 715.21/64=11.175 (11.175-10.5)/.363=1.8595 =1-NORM.S.DIST(1.859,1)=.031

Assume you have applied for two jobs A and B. The probability that you get an offer for job A is 0.25. The probability of being offered job B is 0.20. The probability of getting at least one of the jobs is 0.40. What is the probability that you will be offered both jobs? Enter your answer as a decimal rounded to two places.

.05

The weight of football players for a team is normally distributed with a mean of 275 pounds and a standard deviation of 50 pounds. The probability of a player weighing more than 350 pounds is (Use Excel and round your answer to three decimal places.)

.067 1-NORM.DIST(350,275,50,1)

Consider Question 4, what is the probability that these 64 students spent a combined total between $703.59 and $728.45? Enter your answer as a decimal and not as a percent and round your answer to 3 decimal places.

.079

A very short quiz has one multiple choice question with five possible choices (a, b, c, d, e) and one true or false question. Assume you are taking the quiz but do not have any idea what the correct answer is to either question, but you mark an answer anyway. What is the probability that only your answer to the multiple choice is correct? Enter your answer as a decimal rounded to two decimal places.

.10 (1/2)(1/5) = 1/10)

A very short quiz has one multiple choice question with five possible choices (a, b, c, d, e) and one true or false question. Assume you are taking the quiz but do not have any idea what the correct answer is to either question, but you mark an answer anyway. What is the probability you have given the correct answer to both questions? Enter your answer as a decimal rounded to two decimal places.

.10 (1/2)(1/5) = 1/10)

The SAT scores have an average of 1540 with a standard deviation of 120. A sample of 36 scores is selected. What is the probability that the sample mean will be larger than 1560? Round your answer to three decimal places.

.159 =120/SQRT(36) =1560-1540 =20/20 =1-NORM.S.DIST(1,1)

A basketball player steps to the line to shoot three free-throws. If her free-throw completion average is .935, what is the probability that she completes no more than two? (Round your answer to three decimal places.)

.183 =BINOM.DIST(2,3,0.935,1)

The time required to load a truck is exponentially distributed with a mean of 20 minutes. What is the probability that a truck will be loaded in less than 20 minutes? (Round your answer to 3 decimal places.)

.632 =EXPON.DIST(20,1/20,1)

If P(A) = 0.50, P(B) = 0.40, and P(A intersection B) = 0.20, then P(A union B) =

.7

If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P(A ∪ B) =

.80

Forty percent of the students who enroll in a statistics course go to the statistics laboratory on a regular basis. Past data indicates that 65% of those students who use the lab on a regular basis make a grade of A in the course. On the other hand, only 10% of students who do not go to the lab on a regular basis make a grade of A. If a particular student made an A, determine the probability that she or he used the lab on a regular basis. Enter your answer rounded to four decimal places. Use a tree diagram to answer this question.

.8125 40x.65=26 .1x60=6 26=6=32 26/32=.8125

The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample at least four are female? Use an Excel function and round your answer to three decimal places.

.826 1-BINOM.DIST(3,8,0.6,1)

The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample at most four are male? Use an Excel function and round your answer to three decimal places.

.826 BINOM.DIST(4,8,0.4,1)

The weight of football players for a team is normally distributed with a mean of 275 pounds and a standard deviation of 50 pounds. The probability of a player weighing less than 325 pounds is (Use Excel and round your answer to three decimal places.)

.841 =NORM.DIST(325,275,50,1)

The life expectancy of computer terminals is normally distributed with a mean of 4 years and a standard deviation of 1 year. What is the probability that a terminal will last 5 years or less? Use Excel and round your answer to three decimals

.841 NORM.DIST(5,4,1,1)

The weight of football players for a team is normally distributed with a mean of 275 pounds and a standard deviation of 50 pounds. The probability of a player weighing between 200 and 350 pounds is (Use Excel and round your answer to three decimal places.)

.866 NORM.DIST(350,275,50,1) NORM.DIST(200,275,50,1) 1st-2nd=.866

For a standard normal distribution, determine the probability of obtaining a z value of 1.6 or less. Use Excel and round your answer to three decimal places.

.945 NORM.S.DIST(1.6,1)

Question 2 Consider Question 1, what is the probability that the sample mean will be less than 1230? Round your answer to three decimal places.

.999 1230-1200=30 30/10=3 =NORM.S.DIST(3,1)

The life expectancy of computer terminals is normally distributed with a mean of 4 years and a standard deviation of 1 year. The difference between the probability that the terminal will last three years or less and the probability that the terminal will last less than three years is (Enter your answer as a number with one decimal place.)

0

What is the mean of a standard normal distribution? (Enter your answer as a number rounded to one decimal place.)

0

​If the data distribution is symmetric, the skewness is

0

The range of probability is

0 to 1.

If A and B are mutually exclusive events with P(A) = 0.295, P(B) = 0.32, then P(A | B) =

0.0000. (because they are mutually exclusive)

Four percent of the customers of a mortgage company default on their payments. A sample of five customers is selected. What is the probability that exactly two customers in the sample will default on their payments?

0.0142 Binom Dist 2,5,0.04,0

Question 4 Refer to Questions 2 & 3. The p-value is

0.0228

The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample exactly two are female? Use an Excel function.

0.0413 Binom Dist 2,8,0.6,0

A very short quiz has two multiple choice questions. One question has five possible choices (a, b, c, d, e) and the other has four possible choices (a, b, c, d). Assume you are taking the quiz but do not have any idea what the correct answer is to either of the two questions, but you mark answers anyway. What is the probability you have given the correct answer to both questions? Enter your answer as a decimal rounded to three decimal places.

0.05

Which NCAA college basketball conference has the higher probability of having a team play in a college basketball's national championship game? Over the last 20 years, the Atlantic Coast Conference (ACC) ranks first by having a team in the championship game 10 times. The Southeastern Conference (SEC) ranks second by having a team in the championship game 8 times. However, both conferences have had teams in the championship game only one time, when Arkansas (SEC) beat Duke (ACC) 76-70 in 1994 (NCAA website, April 2009). What is the probability the ACC and SEC will both have teams in the championship game? Round your answer to 3 decimals.

0.05

An experiment consists of four outcomes with P(E1) = 0.2, P(E2) = 0.3, and P(E3) = 0.4. The probability of outcome E4 is

0.100. (add them together)

The manager of a grocery store has taken a random sample of 30 customers. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. If the value of the test statistic is 1.10, what is the p-value of this hypothesis test? Round your answer to three decimal places.

0.14 =1-NORM.S.DIST(1.1,1) or just put in 1.1 in the z value in the first hypo test

Consider Question 4, what is the expected value of the sampling distribution of the sample mean? Round your answer to 2 decimal places and no dollar sign.

10.5 expected value of a sampling distribution is the mean

How many permutations of three items can be selected from a group of six?

120

A committee of 5 is to be selected from a group of 30 people. How many possible different committees can be selected? Use Excel to answer this question.

142,506 =COMBIN(30,5)

From a group of six people, two individuals are to be selected at random. How many selections are possible?

15 ((n! / (x! * (n-x)!) (6! / (2! * 4!))

Playbill Magazine reported that the mean annual household income of its readers is $119,155. Assume this estimate of the mean is based on a sample of 100 households, and based on past studies, the population standard deviation is known to be $18,000. What is the margin of error at a 95% level of confidence? Round your answer to two decimal places and enter it without a dollar sign.

3527.94 put in first confidence interval in excel

How many outcomes are on the roulette wheel shown in class?

38

The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the expected number of females selected? Round your answer to one decimal place.

4.8 8x0.6= 4.8

The numbers of hours worked (per week) by 400 statistics students are shown below. Frequency 20 80 200 100 If a cumulative frequency distribution is developed for the above data, the last class will have a cumulative frequency of

400

Using the Student Survey Data, determine the 75th percentile of Sleep (min.). Enter your answer rounded to two decimal places.

480

From a group of 12 students, we want to select a random sample of 4 students to serve on a university committee. How many combination of random samples of 4 students can be selected?

495 =COMBIN(12,4)

A committee of 4 is to be selected from a group of 12 people. How many possible different committees can be selected? Use Excel to answer this question.

495 (Combin 12,4)

The student body of a very large university consists of 52% female students. A random sample of 10 students is selected. What is the expected number of females selected? Round your answer to one decimal place.

5.2 10x.52=5.2

In order to determine an interval for the mean of a population with unknown standard deviation a sample of 81 items is selected. The mean of the sample is determined to be 23. The number of degrees of freedom for determining the t value to use to create an interval estimate is

80 degrees of freedom is #-1

A professor at a local community college noted that the grades of his students were normally distributed with a mean of 74 and a standard deviation of 10. The professor has informed us that 6.3 percent of his students received A's while only 2.5 percent of his students failed the course and received F's. What is the minimum score needed to earn an A? Enter your answer rounded to one decimal place.

89.3 =NORM.INV(.937,74,10)

Assume your favorite soccer team has 2 games left to finish the season. The outcome of each game can be win, lose or tie. The number of possible outcomes is

9 (multiply them together)

Ten individuals are candidates for positions of president and vice president of an organization. How many possibilities of selections exist?

90 (10 first slot x 9 second slot)

standard normal probability distribution

a normal distribution with a mean of zero and a standard deviation of one

random variable

a numerical description of the outcome of an experiment

An interval estimate is a range of values used to estimate

a population parameter

discrete uniform probability distribution

a probability distribution for which each possible value of the random variable has the same probability

bivariate probability distribution

a probability distribution involving TWO random variables. a discrete bivariate probability distribution provides a probability for each pair of values that may occur for the two random variables

poisson probability distribution

a probability distribution showing the probability of x occurances of an event over a specified interval of time or space

hypergeometric probability distribution

a probability distribution showing the probability of x successes in n trials from a population with r successes and N-r failures

binomial probability distribution

a probability distribution showing the probability of x successes in n trials of a binomial experiment

multiplication law

a probability law used to compute the probability of the intersection of two events

continuous random variable

a random variable that may assume any numerical value in an interval or collection of intervals

discrete random variable

a random variable that may assume either a finite number of values or an infinite sequences of values

A portion of the population selected to represent the population is called

a sample

A graphical presentation of the relationship between two variables is

a scatter diagram

continuity correction factor

a value of .5 that is added or subtracted from a value of x when the continuous normal distribution is used to approximate the discrete binomial distribution

binomial experiment

an experiment having the four properties of when there are two outcomes, the trials are independent, the probability of success, denoted by p, does not change from trial to trial and experiment consists of a sequence of n identical trials

multi-step experiment

an experiment that can be described as a sequence of steps.

If arrivals follow a Poisson probability distribution, the time between successive arrivals must follow

an exponential probability distribution.

experiment

any process that generates well-defined outcomes

relative frequency method

assigning probabilities based on experimentation or historical data

subjective method

assigning probabilities based on judgement

classical method

assigning probabilities based on the assumption of equally likely outcomes

A probability distribution showing the probability of x successes in n trials, where the probability of success does not change from trial to trial, is termed a

binomial probability distribution

The intersection of two mutually exclusive events

can be any value between 0 to 1

In an experiment, events A and B are mutually exclusive. If P(A) = 0.6, then the probability of B

cannot be larger than 0.4.

For ease of data entry into a university database, 1 denotes that the student is an undergraduate and 2 indicates that the student is a graduate student. In this case data are

categorical

For ease of data entry, if we had 1 represent Female and 2 represent Male in the Student Survey Data then Sex would be

categorical

When the assumption of equally likely outcomes is used to assign probability values, the method used to assign probabilities is referred to as the

classical method

When n objects are selected from a set of N objects where order of selection is not important the counting rule is called

combination

The major applications of data mining have been made by companies with a strong _______ focus

consumer

The weight of an object is an example of

continuous random variable

An experiment consists of determining the speed of automobiles on a highway by the use of radar equipment. The random variable in this experiment is a

continuous random variable.

The power curve provides the probability of

correctly rejecting the null hypothesis.

A numerical measure of linear association between two variables is the

covariance.

Data collected at the same, or approximately the same, point in time are

crossectional data

A tabular method that can be used to summarize the data on two variables simultaneously is called

crosstabulation

A graphical tool typically associated with the display of key performance indicators is a

data dashboard.

Different methods of developing useful information from large data bases are dealt with under

data mining.

The process of capturing, storing, and maintaining data is known as

data warehousing.

As the sample size increases, the standard error of the sampling distribution

decreases.

The summaries of data, which may be tabular, graphical, or numerical, are referred to as

descriptive statistics

In a sample of 800 students in a university, 240 or 30% are Business majors. The 30% is an example of

descriptive statistics.

A random variable that can assume only a finite number of values is referred to as a(n)

discrete random variable

The number of customers that enter a store during one day is an example of

discrete random variable

the number of customers that enter a store during one day is an example of

discrete random variable

Quantitative data refers to data obtained with a(n)

either interval or ratio scale

In a crosstabulation​

either or both variables can be categorical or quantitative.

The entities on which data are collected are

elements

mutually exclusive events

events that have no sample points in common

A measure of the average value of a random variable is called a(n)

expected value

Statistical studies in which researchers control variables of interest are

experimental studies

A continuous probability distribution that is useful in describing the time, or space, between occurrences of an event is a(n)

exponential probability distribution

There is a lower limit but no upper limit for a random variable that follows the

exponential probability distribution.

The probability distribution that can be described by just one parameter is the​

exponential.

As the test statistic for an upper tail hypothesis test becomes larger, the p-value

gets smaller

When data are positively skewed, the mean will usually be

greater than the median.

combination

in an experiment we may be interested in determining the number of ways n objects may be selected from among n objects without regard to the order in which n objects are selected

Based on your answer to Question 12, to increase the probability that your sample mean is within a certain range, you would

increase the sample size.

For a given level of Type I error, if we want to decrease the level of Type II error, the sample size must

increase.

Compare your answers to Questions 3 and 11. The probability

increased

probability near one

indicates an event is almost certain to occur

probability near zero

indicates an event is quite unlikely to occur

A sample point refers to the

individual outcome of an experiment

prior probabilities

initial estimates of the probabilities of events

probability of any event

is equal to the sum of the probabilities of the sample point in the event

The probability that a continuous random variable takes any specific value

is equal to zero

In observational studies, the variable of interest

is not controlled

Statistical inference

is the process of drawing inferences about the population based on the information taken from the sample

Michael's Compute-All, a national computer retailer, has kept a record of the number of laptop computers they have sold for a period of 80 days. Their sales records are shown below: The number of days in which the company sold less than 60 laptops is

just add the days together that are under 60 laptops

Refer to Question 1 and assume that the test statistic is 3.96. The p-value is

less than 0.001

Refer to Question 2. If alpha is .05, the correct conclusion is

reject the null hypothesis

Refer to Question 4. If alpha is .05, the correct conclusion is

reject the null hypothesis

Refer to Questions 1 and 2. If alpha is .05, the correct conclusion is

reject the null hypothesis

When the results of experimentation or historical data are used to assign probability values, the method used to assign probabilities is referred to as the

relative frequency method.

posterior probabilities

revised probabilities of events based on additional information

Five hundred residents of Cincinnati are polled to obtain information on voting intentions in an upcoming city election. The five hundred residents in this study is an example of a(n)

sample.

Five hundred residents of a city are polled to obtain information on voting intentions in an upcoming city election. The five hundred residents in this study is an example of a(n)

sample.

The sampled population is the population from which the sample is actually taken.

sampled population

The probability distribution of the sample mean is called the

sampling distribution of the mean

Which of the following graphical methods is used to display and compare two variables?

side-by-side bar chart

​Histograms based on data on housing prices and salaries typically are

skewed to the right.

standard error

standard deviation/sqrt(N)

A normal distribution with a mean of 0 and a standard deviation of 1 is called

standard normal distribution

In a sample of 400 students in a university, 80 or 20% are Business majors. Based on the above information, the school's paper reported that "20% of all the students at the university are Business majors." This report is an example of

statistical inference.

A method of assigning probabilities based upon judgment is referred to as the

subjective method.

A seven-year medical research study reported that women whose mothers took the drug DES during pregnancy were twice as likely to develop tissue abnormalities that might lead to cancer as were women whose mothers did not take the drug. This data was most likely obtained in a

survey.

The target population is the population we want to make inferences about

target population

complement of a

the event consisting of all sample points that are not in A

union of A and B

the event containing all sample points belonging to A or B or both

binomial probability function

the function used to compute binomial probabilities

hypergeometric probability function

the function used to compute hypergeometric probabilities

poisson probability function

the function used to compute poisson probabilities

Temperature is an example of a variable that uses

the interval scale

In the Student Survey Data, the time that a student woke up (Wake) is an example of

the interval scale.

Arithmetic operations are inappropriate for

the nominal scale

In hypothesis testing, the tentative assumption is that

the null hypothesis is true.

When the p-value is used for hypothesis testing, the null hypothesis is rejected if

the p-value is less than or equal to alpha.

Stratified random sampling is a method of selecting a sample in which

the population is first divided into strata, and then random samples are drawn from each stratum

standard deviation

the positive square root of the variance

Bayes' theorem is used to compute

the posterior probabilities

conditional probability

the probability of an event that another event already occured

joint probability

the probability of two events both occurring, the intersection of two events

If two events are independent, then

the product of their probabilities gives their intersection.

The collection of all possible sample points in an experiment is

the sample space.

sample space

the set of all experimental outcomes

For a given sample size in hypothesis testing,

the smaller the Type I error, the larger the Type II error will be.

marginal probability

the values in the margins of a joint probability table that provide the probabilities of two events separately

The cumulative frequency for the class of 20 - 29 Frequency 20 80 200 100

300

z is a standard normal random variable. Compute the probability that z ≥ 2.5. Use Excel and round your answer to three decimal places.

.006 =1-NORM.S.DIST(2.5,1)

normal probability distribution

a continuous probability distribution. its probability density function is bell shaped and determined by its mean and standard deviation

the weight of an object is an example of

a continuous random variable

probability distribution

a description of how the probabilities are distributed over the values of the random variable

z value

((upper limit-mean)/standard error) use norm.s.dist if calculated a z value to find probabilities

The correlation coefficient ranges between

-1 and +1.

Simulation, which is the use of probability and statistical computer models to better understand risk, falls under the category of

. ​predictive analytics.

Reconsider Question 1, but suppose the sample size is 64.

.001

The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample exactly four are female? Use an Excel function and round your answer to three decimal places.

.232 BINOM.DIST(4,8,0.6,0)

Of the last 100 customers entering a computer shop, 25 have purchased a computer. If the classical method for computing probability is used, the probability that the next customer will purchase a computer is

.25

If A and B are independent events with P(A) = 0.3 and P(B) = 0.4, then P(A given B) =

.3

The weight of football players for a team is normally distributed with a mean of 275 pounds and a standard deviation of 50 pounds. The probability of a player weighing less than 250 pounds is (Use Excel and round your answer to three decimal places.)

.309 NORM.DIST(250,275,50,1)

Consider Question 4, what is the standard deviation of the sampling distribution of the sample mean? Round your answer to 3 decimal places and no dollar sign.

.363 =(3/SQRT(64))*SQRT((1000-64)/(1000-1))

A very short quiz has one multiple choice question with five possible choices (a, b, c, d, e) and one true or false question. Assume you are taking the quiz but do not have any idea what the correct answer is to either question, but you mark an answer anyway. What is the probability that neither answer is correct? Enter your answer as a decimal rounded to two decimal places.

.40 ((1/2)(4/5) = 4/10)

A very short quiz has one multiple choice question with five possible choices (a, b, c, d, e) and one true or false question. Assume you are taking the quiz but do not have any idea what the correct answer is to either question, but you mark an answer anyway. What is the probability that you have only answered the true or false question correctly? Enter your answer as a decimal rounded to two decimal places.

.40 ((1/2)(4/5) = 4/10)

The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample at most four are female? Use an Excel function and round your answer to three decimal places.

.406 BINOM.DIST(4,8,0.6,1) cumulative

Consider Question 1, what is the probability that the sample mean will be between 1200 and 1214? Round your answer to three decimal places.

.419 1214-1200=14 14/10=1.4 =NORM.S.DIST(1.4,1)=.919 1200-1200=0 =NORM.S.DIST(0,1)=.5 .919-.5=.419

Reconsider Question 3 with the sample size of 64

.469

What is the probability of red on the roulette wheel? Enter your answer as a decimal rounded to three decimal places.

.474 (36/2=18 18/38=.474)

The time required to load a truck is exponentially distributed with a mean of 15 minutes. What is the probability that a truck will be loaded in 10 minutes or less? Enter your answer as a decimal not as a percent and round your answer to 3 decimal places.

.487 EXPON.DIST(10,1/15,1)

A very short quiz has one multiple choice question with five possible choices (a, b, c, d, e) and one true or false question. Assume you are taking the quiz but do not have any idea what the correct answer is to either question, but you mark an answer anyway. What is the probability that only one of the two answers is correct? Enter your answer as a decimal rounded to two decimal places.

.50 (1 - [both right or both wrong] = 1 - [1/10 + (1/2)(4/5)] = 1-[1/2] = 1/2)

The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample more than four are female? Use an Excel function and round your answer to three decimal places.

.594 1-BINOM.DIST(4,8,0.6,1) cumulative and subtract from 1

Suppose you first randomly sample one card from a deck of 52. Then, without putting the card back in the deck you sample a second and then (again without replacing cards) a third. Given this sampling procedure, what is the probability that exactly one of the three sampled cards will be an ace (4 of the 52 cards in the deck are aces)? Round your answer to three decimal places.

0.204

The average number of cars that pass through a rural intersection in a fifteen minute interval is 5.4. It can be assumed that the probability of an occurrence is the same in any two-time periods of equal length. Determine the probability that there are 3 occurrences or less in fifteen minutes. Enter your answer as a decimal rounded to three places.

0.213 =POISSON.DIST(3,5.4,1)

Poisson distribution.

a discrete frequency distribution that gives the probability of a number of independent events occurring in a fixed time.

The time required to load a truck is exponentially distributed with a mean of 15 minutes. What is the probability that a truck will be loaded in more than 10 minutes but less than 20 minutes? Enter your answer as a decimal not as a percent and round your answer to 3 decimal places.

0.25 EXPON.DIST(20,1/15,1) EXPON.DIST(10,1/15,1) first- second=.25

If A and B are independent events with P(A) = 0.38 and P(B) = 0.55, then P(A given B) =

0.38

The assembly time for a product is uniformly distributed from 5 to 10 minutes. The probability of assembling the product in less than 7 minutes is

0.4 2/5=.4

The assembly time for a product is uniformly distributed between 6 to 10 minutes. The probability of assembling the product between 7 to 9 minutes is

0.50

empirical discrete distribution

a discrete probability distribution for which the relative frequency method is used to assign the probabilities

The student body of a very large university consists of 60% female students. A random sample of 10 students is selected from the class. What is the probability that among the students in the sample at least 6 are female? Use an Excel function and round your answer to three decimal places.

0.633

If A and B are independent events with P(A) = 0.2 and P(B) = 0.6, then P(A union B) =

0.68 P( A U B ) = P( A ) + P( B ) - P( A ∩ B ) P( A ∩ B ) = P( A ) ● P ( B ) = 0.2 ● 0.6 = 0.12 P( A U B ) = 0.2 + 0.6 - 0.12 = 0.68

If P(A) = 0.50, P(B) = 0.60, and P(A intersection B) = 0.30, then P(A union B) =

0.80 P(A)+P(B)-P(A intersection B) .5+.6=1.1-.3=.8

Events A and B are mutually exclusive with P(A) = 0.3 and P(B) = 0.2. Then, P(B^c) =

0.80.

One of the questions in the Pew Internet & American Life Project asked adults if they used the Internet at least occasionally (Pew website, October 23, 2012). The results showed that 454 out of 478 adults aged 18 - 29 answered Yes; 741 out of 833 adults aged 30 - 49 answered Yes; 1058 out of 1644 adults aged 50 and over answered Yes. Develop a point estimate of the proportion of adults aged 18 - 29 who use the Internet. Round your answer to four decimal places.

0.9498 454/478=.9498

The probability distribution for the number of goals the Lions soccer team makes per game is given below. Number Of Goals Probability 0=0.05 1=0.15 2=0.35 3=0.30 4=0.15 What is the probability that in a given game the Lions will score at least 1 goal?

0.95 .15+.35+.30+.15=.95 everything but 0 goals

Reconsider Question 2 and the new sample size of 64.

1

A lottery is conducted using three urns. Each urn contains chips numbered from 0 to 9. One chip is selected at random from each urn. The total number of sample points in the sample space is

1,000 (10x10x10) (0 is included so it makes it 10 numbers)

A random sample of 50 SAT scores of students applying for merit scholarships showed an average of 1600 with a standard deviation of 200. Determine the upper limit of a 95% interval estimate for the population mean. Round your answer to two decimal place.

1,656.84 just put in first confidence interval in excel

The sum of the probabilities of two complementary events is

1.0

The average annual cost of the first year of owning and caring for a large dog is $1843 (US News and World Report, September 9, 2013). The Irish Red and White Setter Association of America has requested a study to estimate the annual first-year cost for owners of this breed. The sample of 50 produces a mean of $1836.84. Based on past studies, the population standard deviation is assumed known with σ = $255. Determine the lower limit of a 95% interval estimate for the population mean. Round your answer to two decimal places and enter it without a dollar sign.

1766.16 type into first confidence interval

The American Statistical Association approved the report "Ethical Guidelines for Statistical Practice" in

1999

Random samples of size 100 are taken from an infinite population whose mean and standard deviation are 250 and 20, respectively. The distribution of the population is unknown. The standard error of the sampling distribution is

2 standard error = std dev/sample size

Question 3 Refer to Question 2. The value of the test statistic is

2.0

Question 1 The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes with a standard deviation of 0.5 minutes. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. The test statistic is

2.00 =(3-3.1)/(0.5/SQRT(100))

The manager of a grocery store has taken a random sample of 30 customers. The average length of time it took the customers in the sample to check out was 3.2 minutes with a standard deviation of 0.5 minutes. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. What is the value of the test statistic? Round your answer to two decimal places.

2.19 type into hypo test 2

The probability distribution for the number of goals the Lions soccer team makes per game is given below. Number Of Goals Probability 0=0.05 1=0.15 2=0.35 3=0.30 4=0.15 the expected number of goals per game is

2.35 .6+.9+.7+.15=2.35 everything but 0

Assuming that each of the 52 cards in an ordinary deck has a probability of 1/52 of being drawn, what is the probability of drawing a black ace?

2/52

Random samples of size 81 are taken from an infinite population whose mean and standard deviation are 200 and 18, respectively. The distribution of the population is unknown. The mean and the standard error of the distribution of the sample mean are

200 and 2

An experiment consists of three steps. There are four possible results on the first step, three possible results on the second step, and two possible results on the third step. The total number of experimental outcomes is

24. (multiply them together)

Random samples of size 100 are taken from an infinite population whose mean and standard deviation are 250 and 20, respectively. The distribution of the population is unknown. The mean of the sampling distribution is

250 it tells you the answer

The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the expected number of males selected? Round your answer to one decimal place.

3.2 0.6x8=4.8 8-4.8=3.2

"DRUGS R US" is a large manufacturer of various kinds of liquid vitamins. The quality control department has noted that the bottles of vitamins marked 6 ounces vary in content with a mean of 6 ounces and a standard deviation of 0.3 ounces. Assume the contents of the bottles are normally distributed. Ninety-five percent of the bottles will contain at least how many ounces? Round your answer to 2 decimal places.

5.51 =NORM.INV(.05,6,.3)

"DRUGS R US" is a large manufacturer of various kinds of liquid vitamins. The quality control department has noted that the bottles of vitamins marked 6 ounces vary in content with a mean of 6 ounces and a standard deviation of 0.3 ounces. Assume the contents of the bottles are normally distributed. Ninety-five percent of the bottles will contain less than how many ounces? Round your answer to 2 decimal places.

6.49 =NORM.INV(.95,6,.3) less than is .95

Use the Student Survey Data and an Excel PivotTable to determine the number of students who slept between 420 and 479 minutes. Group the data starting at 60, ending at 600 by 60.

62

A survey of 800 college seniors resulted in the following crosstabulation regarding their undergraduate major and whether or not they plan to go to graduate school.

65% 520/800

Use the Student Survey Data and an Excel PivotTable to determine the percentage of students who slept less than 480 minutes. Group the data starting at 60, ending at 600 by 60. Enter your answer as a percentage rounded to two decimal place and without a percent sign.

67.57

The empirical rule states that, for data having a bell-shaped distribution, the percentage of data values being within one standard deviation of the mean is approximately​

68%

The assembly time for a product is uniformly distributed between 6 to 10 minutes. The expected assembly time (in minutes) is

8

A psychologist developed a new test of adult intelligence. The test was administered to 20 individuals, and the following data were obtained. 124 109 141 134 127 111 115 137 129 125 108 113 154 164 142 115 135 132 128 128 If you construct a stem-and-leaf display for the data, using a leaf unit of 1, the first leaf in the first stem would be

8 lowest number

The union of events A and B is the event containing all the sample points belonging to

A or B or both.

addition law

A probability law used to compute the probability of the union of two events.

A Type II error is committed when

a false null hypothesis is not rejected.

probability function

a function denoted by F(x) that provides the probability that x assumes a particular value for a discrete random variable

permutation

An arrangement of objects in which order is important

probability density function

a function used to compute probabilities for a continuous random variable. the are under the graph of a probability density function over an interval represents probability

If the probability of a Type I error (α) is .05, then the probability of a Type II error (β) must be

Cannot be computed.

expected value

a measure of the central location of a random variable

Social security numbers consist of numeric values. Therefore, social security is an example of

a categorical variable

event

a collection of sample points

uniform probability distribution

a continuous probability distribution for which the probability that the random variable will assume a value in any interval is the same for each interval of equal length

Which of the following is a characteristic of an experiment where the binomial probability distribution is applicable?

Exactly two outcomes are possible on each trial

In the textile industry, a manufacturer is interested in the number of blemishes or flaws occurring in each 100 feet of material. The probability distribution that has the greatest chance of applying to this situation is the

Poisson distribution.

exponential probability distribution

a continuous probability distribution that is useful in computing probabilities for the time it takes to complete a task

The average life expectancy of tires produced by the Whitney Tire Company has been 40,000 miles. Management believes that due to a new production process, the life expectancy of their tires has increased. In order to test the validity of their belief, the correct set of hypotheses is

H0: the population mean is less than or equal to 40,000 Ha: the population mean is greater than 40,000

In the Simpson's Paradox example in the text, which judge had the better record in the unaggregated data?

Judge Luckett

If you created a bar chart showing the frequency of Birth Month (Bmonth) using the Student Survey Data, the Birth Month with the tallest bar would be

June

​Generally, which one of the following is the least appropriate measure of central tendency for a data set that contains outliers?

Mean

As the sample size becomes larger, the sampling distribution of the sample mean approaches a

Normal distribution

Finite populations are often defined by lists such as:

Organization membership roster Credit card account numbers Inventory product numbers

The average hourly wage of computer programmers with 2 years of experience has been $21.80. Because of high demand for computer programmers, it is believed there has been a significant increase in the average hourly wage of computer programmers. To test whether or not there has been an increase, the correct null hypothesis to be tested is

The average hourly wage is less than or equal to 21.80.

A juice drink filling machine, when in perfect adjustment, fills the bottles with 12 ounces of drink on an average. Any overfilling or underfilling results in the shutdown and readjustment of the machine. To determine whether or not the machine is properly adjusted, the correct alternative hypotheses is

The average is not equal to 12 ounces.

Decide whether each situation demonstrates a discrete or continuous random variable.

The number of penalties in a football game Discrete The number of yellow M&Ms in a bowl of candy Discrete Your weight in kilograms Continuous The distance to your home in miles Continuous The number of students in this room Discrete

bayes theorem

a method used to compute posterior probabilites

What type of error occurs if you reject H0 when, in fact, it is true?

Type I

What type of error occurs if you fail to reject H0 when, in fact, it is not true?

Type II

Question 2 The sales of a grocery store had an average of $8,000 per day. The store introduced several advertising campaigns in order to increase sales. To determine whether or not the advertising campaigns have been effective in increasing sales, a sample of 64 days of sales was selected. It was found that the average was $8,300 per day. From past information, it is known that the standard deviation of the population is $1,200. The correct null hypothesis for this problem is

m is less than or equal 8000

The value added and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the

margin of error

Categorical data

may be either numeric or non-numeric

If two events, A and B, are mutually exclusive, the probability of A intersection B

must always be equal to 0

In logic and probability theory, two propositions (or events) are mutually exclusive or disjoint if they cannot both be true (occur). A clear example is the set of outcomes of a single coin toss, which can result in either heads or tails, but not both.

mutually exclusive

In computing the standard error of the mean, the finite population correction factor is used when

n/N > 0.05

Smaller values of the standard deviation result in a normal curve that is

narrower and more peaked

If the data distribution is skewed to the left, the skewness is

negative

​For data skewed to the left, the skewness is

negative

In a questionnaire, respondents are asked to mark their gender as male or female. Gender is an example of the

nominal scale

The data measured on ordinal scale exhibits all the properties of data measured on

nominal scale.

Question 4 A population of 1,000 students spends an average of $10.50 a day on dinner. The standard deviation of the expenditure is $3. A simple random sample of 64 students is taken. What is the shape of the sampling distribution of the sample mean?

normal

The set of measurements collected for a particular element is (are) called

observations

Some hotels ask their guests to rate the hotel's services as excellent, very good, good, and poor. This is an example of the

ordinal scale

In the Student Survey Data, Birth Month is an example of the

ordinal scale.

Some examples of on-going processes with infinite populations are

parts being manufactured on a production line transactions occurring at a bank telephone calls arriving at a technical help desk customers entering a store

The purpose of statistical inference is to provide information about the

population based upon information contained in the sample

Positive values of covariance indicate

positive relation between the independent and the dependent variables.

When the null hypothesis is not rejected, it is​

possible a Type II error has occurred.

a numerical measure of the likelihood that an event will occur. the values are always assigned on a scale from 0 to 1

probability

The function that defines the probability distribution of a continuous random variable is a

probability density function

Chapter 5 focuses on

probability distributions

An insurance company selected samples of clients under 18 years of age and over 18 and recorded the number of accidents they had in the previous year. The results are shown below. Under Age of 18 n1 = 500 Number of accidents = 180 Over Age of 18 n2 = 600 Number of accidents = 150 We are interested in determining if the accident proportions differ between the two age groups. Let pu represent the proportion under and po the proportion over the age of 18. The null hypothesis is

pu - po = 0

The weight of a candy bar in ounces is an example of

quantitative data.

In the Student Survey Data, Sleep(min.) is an example of a variable that uses the

ratio scale

Income is an example of a variable that uses the

ratio scale

Data collected over several time periods are

time series data

If a histogram is said to be skewed to the right it has a longer tail

to the right as compared to the left

A graphical device used for enumerating sample points in a multiple-step experiment is a

tree diagram

independent events

two events A and B that the events have no influence on each other

Larger values of the standard deviation result in a normal curve that is

wider and flatter

If the level of significance of a hypothesis test is raised from .01 to .05, the probability of a Type II error

will decrease.

The assembly time for a product is uniformly distributed between 6 to 10 minutes. The probability of assembling the product in less than 6 minutes is

zero

​Statements about the proportion of data values that must be within a specified number of standard deviations of the mean can be made using

​Chebyshev's theorem.

Which of the following are continuous random variables?​ I. The weight of an elephant II. The time to answer a questionnaire III. The number of floors in a skyscraper IV. The square feet of countertop in a kitchen

​I, II and IV only

When the conclusions based upon the unaggregated data can be completely reversed if we look at the aggregated crosstabulation, the occurrence is known as

​Simpson's paradox.

A box plot is a graphical representation of data that is based on

​a five number summary.

​Optimization models, which generate solutions that maximize or minimize some objective subject to a set of constraints, fall into the category of

​prescriptive analytics.

In stratified random sampling,​

​randomly selected elements within each of the strata form the sample.

​A mean computed in such a way that each data value is given a weight reflecting its importance is referred to as a

​weighted mean.