final

The following stem-and-leaf diagram shows the last 20 dividend payments (in cents) paid by Procter and Gamble. The most common dividend payment is

0.44

According to the Bureau of Justice Statistics, 10% of persons age 16 or older had been victims of identity theft during the prior 12 months in 2016. What is the minimal sample size of a random sample of persons age 16 or older to generate a normal distribution approximation?

50

Sarah's portfolio has an expected annual return at 10%, with an annual standard deviation at 12%. If her investment returns are normally distributed, then in any given year Sarah has an approximate ________.

68% chance that the actual return will fall within −2% and 22%

For any population proportion p, the sampling distribution of P⎯⎯⎯P¯ will be approximately normal if the sample size n is sufficiently large. As a general guideline, the normal distribution approximation is justified when np ≥ 5 and n(1 − p) ≥ 5.

TRUE

If a small segment of the population is sampled then an estimate will be less precise.

TRUE

In a data set, an outlier is a large or small value regarded as an extreme value in the data set.

TRUE

In a one-tailed test, the rejection region is located under one tail (left or right) of the corresponding probability distribution, while in a two-tailed test this region is located under both tails.

TRUE

Mutually exclusive and collectively exhaustive events contain all outcomes of a sample space, and they do not share any common outcomes.

TRUE

Nonresponse bias occurs when those responding to a survey or poll differ systematically from the nonrespondents.

TRUE

Social-desirability bias refers to systematic difference between a group's "socially acceptable" responses to a survey or poll and this group's ultimate choice.

TRUE

The Sharpe ratio measures the extra reward per unit of risk.

TRUE

The coefficient of variation is a unit-free measure of dispersion.

TRUE

The empirical rule is only applicable for approximately bell-shaped data.

TRUE

The main ingredient for developing a confidence interval is the sampling distribution of the underlying statistic.

TRUE

The required sample size for the interval estimation of the population mean can be computed if we specify the population standard deviation σ, the value of zα/2zα/2 based on the confidence level 100(1 − α)% and the desired margin of error E.

TRUE

The tdf distribution has broader tails than the z distribution.

TRUE

Time series data contain values of a characteristic of a subject over time.

TRUE

A pension plan gives you 12 possible funds in which to invest, but you are allowed to hold four at any given point in time. How many possible combinations of the 12 funds could you have in your portfolio?

The Excel function used is =COMBIN(12,4) = 495

Confidence intervals of the population mean may be created for the cases when the population standard deviation is known or unknown. How are these two cases treated differently?

Use the z table when σ is known; use the t table when σ is unknown.

What is(are) the most widely used measure(s) of dispersion?

Variance and standard deviation

If Y = eX has a lognormal distribution, what can be said of the distribution of the random variable X?

X follows a normal distribution.

A random sample of 150 cast aluminum pots is taken from a production line once every day. The number of defective pots is counted. The proportion of defective pots has been closely examined in the past and is believed to be 0.04. The sample proportions for the week are shown in the accompanying table.

Yes, because the sample proportions fall within the upper and lower control limits

A normal random variable X has a mean of 17 and a variance of 5. Find the value x for which P(X ≤ x) = 0.0020. Find the value of x for which P(X > x) = 0.0122.

a) The appropriate Excel function is =NORM.INV(0.002,17,SQRT(5)) = 10.56 b) The appropriate Excel function is =NORM.INV(1-0.0122,17,SQRT(5)) = 22.03

Which of the following variables are categorical and which are numerical? If the variable is numerical, then specify whether the variable is discrete or continuous. a. Points scored in a football game. b. acial composition of a high school classroom. c. Numerical; continuous Correct

a. Numerical; discrete b. Categorical c. Numerical; continuous

The normal distribution is ______ in the sense that the tails get closer and closer to the horizontal axis but never touch it.

asymptotic

A & B A & C A & D B & C

yes. no no. no no no yes. no

A discrete variable cannot assume an infinite number of values

FALSE

Events are exhaustive if they do not share common outcomes of a sample space.

FALSE

Examples of random variables that closely follow a normal distribution include the age and the class year designation of a college student.

FALSE

For any sample size n, the sampling distribution of X⎯⎯⎯X¯ is normal if the population from which the sample is drawn is uniformly distributed.

FALSE

In cluster random sampling, the population is first divided up into mutually exclusive and collectively exhaustive groups, called clusters. A cluster sample includes randomly selected observations from each cluster, which are proportional to the cluster's size.

FALSE

Like the z distribution, the tdf distribution is symmetric around 0, bell-shaped, and with tails that approach the horizontal axis and eventually cross it.

FALSE

The complement of an event A, denoted by AC, within the sample space S, is the event consisting of all outcomes of A that are not in S.

FALSE

The letter Z is used to denote a random variable with any normal distribution.

FALSE

The mean and standard deviation of the continuous uniform distribution are equal.

FALSE

The variance and standard deviation are the most widely used measures of central location.

FALSE

We are often interested in finding the probability that a continuous random variable assumes a particular value.

FALSE

We use a population parameter to make inferences about a sample statistic.

FALSE

The confidence coefficient is equal to

1 - a

If an exponential distribution has the rate parameter λ = 5, what is its expected value?

1/5

An experiment consists of tossing three fair coins. What is the probability of tossing two tails?

3/8

According to the IRS, the average refund in the 2011 tax year was $3,109. Assuming that the standard deviation for these refunds was $874, what is the standard error of the sample mean for a random sample of 50 tax returns?

=874/SQRT(50) = $123.60

The Japan Sumo Association has begun to measure the body fat of wrestlers to try to combat the growing problem of excessive obesity within the sport. As of last year, the average wrestler weighed 412 pounds. Suppose the weights of sumo wrestlers are normally distributed, with a standard deviation of 37 pounds. What is the probability that a randomly selected wrestler weighs between 350 and 450 pounds?

=NORM.DIST(450,412,37,TRUE) -NORM.DIST(350,412,37,TRUE) = 0.8009

A university administrator expects that 25% of students in a core course will receive an A. He looks at the grades assigned to 60 students. What are the expected value and the standard error for the proportion of students that receive an A?

=SQRT(0.25*(1-0.25)/60) = 0.0559

Which of the following is correct?

A continuous random variable has a probability density function, and a discrete random variable has a probability mass function.

Statisticians like precision in their interval estimates. A low margin of error is needed to achieve this. Which of the following supports this when selecting sample sizes?

A larger sample size reduces the margin of error.

Which of the following statements is FALSE regarding the given curves showing the shapes of the probability density function for various values of mean and standard deviation?

All three curves are depicting a standard normal distribution.

Consider these events. A = The survey respondent is less than 40 years old. B = The survey respondent is 40 years or older. Events A and B are mutually exclusive and exhaustive.

TRUE

A university interested in tracking its honors program believes that the proportion of graduates with a GPA of 3.00 or below is less than 0.20. In a sample of 200 graduates, 30 students have a GPA of 3.00 or below. In testing the university's belief, how does one define the population parameter of interest?

It's the proportion of honors graduates with a GPA of 3.00 or below.

If A and B are independent events, which of the following is correct?

P(AB)=P(A)P(AB)=P(A)

A daily mail is delivered to your house between 1:00 p.m. and 6:00 p.m. Assume delivery times follow the continuous uniform distribution. Determine the percentage of mail deliveries that are made after 3:00 p.m.

Probability = (6 − 3)/(6 − 1) = 60%.

0! = 0.

TRUE

A contingency table shows the frequencies for two categorical variables.

TRUE

Approximately 60% of the observations in a data set fall below the 60th percentile.

TRUE

What does the covariance measure?

The direction of a linear relationship between two variables.

What is the relationship between the variance and the standard deviation?

The standard deviation is the positive square root of the variance.

A survey is designed to collect data on students' evaluations of their instructor's teaching performance. Which of the following situations most likely results in social-desirability biases?

The survey is administered in class with the instructor in the room the entire time.

Which of the following statements regarding the sampling distribution of the sample mean is TRUE?

The variance of the sample mean is smaller than the variance of all individual observations in the population.

The ___________ determine the extent of the broadness of the tails of the distribution.

degrees of freedom

According to the ________, if we flip a fair coin a large number of times, tails will shows up ______% of the time.

bials, 50%

A(n) __________ variable is characterized by infinitely uncountable values and can take any value within interval.

continuous

Consider the following hypotheses that relate to the medical field: H0: A person is free of disease. HA: A person has disease. In this instance, a Type II error is often referred to as

false negative

What graphical tool is best used to display the relative frequency of a numerical variable?

histogram

A car company wants to know the average age of cars of their brand that are still on the road. How would you define the appropriate population? Will the car company calculate a population parameter or a sample statistic? Why?

i would define the appropriate population by calculating in a small rural area the average age of the cars. it would be a sample statistic because it would be a lot easier and cheaper to find this information rather than finding every single car out there

A company has developed a new diet that it claims will lower one's weight by more than 10 pounds. Health officials decide to conduct a test to validate this claim. The manager of the company

is more concerned about Type II error

A confidence interval is generally associated with a(n) _____________.

margin of error

A company has developed a new diet that it claims will lower one's weight by more than 10 pounds. Health officials decide to conduct a test to validate this claim. The consumers should be __________.

more concerned about Type I error

To construct a 95% confidence interval for µ, the sampling distribution of X⎯⎯⎯X¯ must be _______.

normal

A company decided to test the hypothesis that the average time a company's employees are spending to check their private e-mails at work is more than 6 minutes. A random sample of 40 employees were selected and they averaged 6.6 minutes. It is believed that the population standard deviation is 1.7 minutes. The α is set to 0.05. The p-value for this hypothesis test would be

p-value = 1-NORM.S.DIST((6.6-6)/(1.7/SQRT(40)),TRUE) = 0.0128

A __________ represents all possible subjects of interest.

population

Data that describe a characteristic about a sample is known as a

statistic

A(n) _____ _____ of an experiment records all possible outcomes of the experiment.

statistical inference

Given the __________ of the z distribution, the p-value for a two-tailed test is twice that of the p-value for a one-tailed test.

symmetry

Which of the following variables is quantitative?

temperature

A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 4.00. A sample of 36 honors students is taken and is found to have a mean GPA equal to 4.10. The population standard deviation is assumed to equal 0.40. The parameter to be tested is __________.

the mean GPA of the university honors students

The __________ identifies the number of standard deviations a particular value is from the mean of its distribution.

z score