DSC Final

An important numerical measure related to the shape of a distribution is the _____.

Skewness

This sampling method involves breaking the population up into subgroups and taking a simple random sample from each of the subgroups.

Stratified Random Sampling

Taking repeated samples until you obtain the desired result is not an ethically acceptable statistical practice.

True

The Empirical Rule can only be applied if the data distribution is bell-shaped.

True

The level of significance α (alpha) is the probability that the confidence interval does not contain the value of the parameter being estimated.

True

The median is used in creating a boxplot.

True

The monthly number of applications for admission to UD is a discrete random variable.

True

The sample mean provides a point estimate for the population mean.

True

A company wants to enhance the benefits for its yearly healthcare package offering. It observes the set of employees who smoke on their break times at 10 a.m., 12 p.m., and 2 p.m. It records the number of cigarettes smoked by each individual. This is an example of:

Observational

Events A and B are mutually exclusive. Which of the following statements is also true?

P(A ∪ B) = P(A) + P(B)

Excel's __________ can be used to construct a crosstabulation.

Pivot Table Tool

If one wanted to find the probability of 10 customer arrivals in an hour at a service station, one would generally use the _____.

Poisson

Every confidence interval constructed will contain the value of the parameter being estimated.

False

Highway patrol officers measure the speed of automobiles on a highway using radar equipment. The random variable in this experiment is speed, measured in miles per hour. This random variable is a discrete random variable.

False

In a crosstabulation, both variables must be quantitative.

False

In combinations, the order of selection is important.

False

Numerical calculations are always appropriate for nominal data.

False

The Central Limit Theorem can only be used when the population being sampled is normally distributed.

False

The RAND() function in Excel can be used to find a probability.

False

The correlation coefficient can never be negative.

False

The mean is a better measure of center than the median if there is an outlier in the data set.

False

Events A and B are mutually exclusive with P(A) = .3 and P(B) = .2. The probability of the complement of event B equals _____.

.8= (1-.2)

If A and B are mutually exclusive events with P(A) = .5 and P(B) = .5, then P(A ∩ B) is _____.

0

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

When the population has a normal distribution, the sampling distribution of is normally distributed _____.

for any sample size

On a December day, the probability of snow is .30. The probability of a "cold" day is .50. The probability of snow and a "cold" day is .15. Thus, snow and "cold" weather are _____.

independent events

All of the following are true about the standard error of the mean EXCEPT _____.

it is larger than the standard deviation of the population

The coefficient of variation indicates how large the standard deviation is relative to the _____.

mean

The expected value of a random variable is the _____.

mean value

After the data have been arranged from smallest value to largest value, the value in the middle is called the

median

To compute a binomial probability. we must know all of the following except the _____.

number of elements in the population

The interquartile range is used as a measure of variability to overcome what difficulty of the range?

outliers/ extreme values

The binomial probability distribution is most symmetric when _____.

p = .05

A single numerical value used as an estimate of a population parameter is known as a _____.

point estimate

The general form of an interval estimate of a population mean or population proportion is the _____ plus or minus the _____.

point estimate, margin of error

A description of how the probabilities are distributed over the values the random variable can assume is called a(n) _____.

probability distribution

The key difference between binomial and hypergeometric distributions is that with the hypergeometric distribution the _____.

probability of success changes from trial to trial

Forty percent of all registered voters in a national election are female. A random sample of 5 voters is selected. What is the random variable in this experiment?

the number of female voters out of 5

A graphical method of representing the sample points of a multiple-step experiment is a(n) _____.

tree diagram

The symbol for the sample variance is s2.

true

The symbol ∪ indicates the _____.

union of events

If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the _____.

width of the confidence interval to increase

Which of the following symbols represents the standard deviation of a population?

σ

If events A and B are independent, then P(A|B) = P(A) + P(B).

FALSE

The Poisson random variable is an example of a continuous random variable.

FALSE

A histogram is appropriate to be used for categorical data.

False

An interval estimate provides a single value estimate for a population parameter.

False

If A and B are independent events with P(A) = .2 and P(B) = .6, then P(A ∪ B) = _____.

.68

A proficiency exam was given to employees of a firm. 60% of the firm's employees passed the exam. 30% of the employees are male. The probability that an employee was female and passed the examination was 0.56. What is the probability that a randomly selected employee is female or passed the exam?

.74

If P(A) = .62, P(B) = .56, and P(A ∪ B) = .70, then P(B | A) = _____.

.7742

A proficiency exam was given to employees of a firm. Seventy percent of the firm's employees passed the exam. The probability that an employee was female and passed the examination was 0.56. If a randomly selected employee passed the exam, what is the probability that the employee is a female?

.80

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

The use of the normal probability distribution as an approximation of the sampling distribution of is based on the condition that both np and n (1 - p) equal or exceed _____.

5

Frequency Distribution

A tabular summary of data showing the number (frequency) of observations in each of several non-overlapping categories or classes.

The binomial probability distribution is appropriate to use for "without replacement" type problems.

FALSE

Posterior probabilities are computed using _____

Bayes Theorem

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

All of the following are examples of observational studies except:

C A. an online survey to record your satisfaction with a company's service. B. the number of cars running a stop sign in a residential area during rush hour. C. the behavior of Walmart shoppers after they are given a $20 gift card from the store. D. a Gallup poll measuring the approval rating of the president.

The fact that the sampling distribution of the sample mean can be approximated by a normal probability distribution whenever the sample size is large is based on the _____.

CLT

In a post office, the mailboxes are numbered from 1 to 5,000. These numbers represent

Categorical Data

The number of observations in a complete data set having 20 elements and 3 variables is:

D A. 20 + 3 or 23. B. 20*3 or 60. C. 20 - 3 or 17. D. 20.

Examples of categorical data include all of the following except:

D A. extra large. B. blonde. C. 90210 (Beverly Hills). D. 228 lbs.

A set of visual displays that organizes and presents information that is used to monitor the performance of a company or organization in a manner that is easy to read, understand, and interpret is called a:

Data Visualization

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

Descriptive Statistics

Mutually exclusive events are dependent.

TRUE

Which of the following would likely display a negative relationship when creating a scatter diagram?

The number of classes a student misses during a semester and the grade obtained in the course

The standard deviation of all possible values is called the _____.

The standard error of the mean

Which of the following is NOT a characteristic of an experiment where the binomial probability distribution is applicable?

The trials are dependent

A pie chart is appropriate for categorical data.

True

A prediction made from sample data is an example of an inferential statistic.

True

Cluster sampling is a probability-based sampling method.

True

Which of the following is NOT a probability-based sampling method?

Volunteer Sampling

The _____ denotes the number of standard deviations x bar is from the mean .

Z score

A continuous random variable may assume _____.

any value in an interval or collection of intervals

A graphical summary of data that is based on a five-number summary is a _____.

boxplot

Probability values must be ____________________.

between 0 to 1, inclusive.

The weight of an object, measured in grams, is an example of _____.

continuous random variable

The t distribution is a family of similar probability distributions, with each individual distribution depending on a parameter known as the _____.

degrees of freedom

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

discrete random variable

Which of the following is a point estimator?

s

The margin of error in an interval estimate of the population mean is a function of all of the following EXCEPT _____.

sample mean

Whenever the population standard deviation is unknown, which distribution is used in developing an interval estimate for a population mean?

t distribution

If two events are independent, then _____.

the events have no influence on each other

The probability Pete will catch fish when he goes fishing is .8. Pete is going fishing 3 days next week. The random variable in this problem is ______________________________________________.

the number of days out of 3 that Pete catches fish