BSTAT - Exam 1 Review

Consider the following frequency distribution. Class. Frequency 12 up to 15 3 15 up to 18 6 18 up to 21 3 21 up to 24 4 24 up to 27 4 The total number of observations in the frequency distribution is ______.

20

A city in California spent $6 million repairing damage to its public buildings in Year 1. The following table shows the categories where the money was directed. Cause. Percent Termites 22% Water Damage 6% Mold 12% Earthquake 27% Other 33% How much more did the city spend to fix damage caused by termites compared to the damage caused by water?

$960,000

In a histogram, the proportion of the total area which must be to the right of the mean is: - more than 0.50 if the distribution is skewed to the right. - less than 0.50 if the distribution is skewed to the left. - exactly 0.50 if the distribution is bell shaped and unimodal. - exactly 0.50.

exactly 0.50 if the distribution is bell shaped and unimodal.

Which measure of central tendency can be used for both numerical and categorical variables?

mode

The _______ identifies the number of standard deviations a particular value is from the mean of its distribution. - median - z-score - coefficient of variation - empirical rule

z-score

In general, the scatter diagram of two interval variables may reveal that: - there is a negative linear relationship. - All of these choices are true statements. - there is no relationship at all, or the relationship may be nonlinear. - there is a positive linear relationship.

All of these choices are true statements.

Which of the following represents a population and a sample from that population? - Full-time employees at a marketing firm, and temporary summer interns at the marketing firm - Seniors at Boston College and students in a first-semester business statistics course - Attendees at a sporting event, and those who purchased popcorn at said sporting event - Stocks available on the NYSE and stocks on the NASDAQ

Attendees at a sporting event, and those who purchased popcorn at said sporting event

A pie chart is a segmented circle that portrays the categories and relative sizes of some quantitative variable.

False

Cross-sectional data contain values of a characteristic of one subject collected over time.

False

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

False

Mean-variance analysis suggests that investments with lower average returns are also associated with higher risks.

False

Population parameters are used to estimate corresponding sample statistics.

False

Statistics is the methodology of extracting unnecessary information from a data set.

False

The arithmetic mean is the middle value of a data set.

False

The empirical rule is applicable for approximately all shapes of data.

False

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

False

Which of the following best describes a frequency distribution for qualitative data? - It groups data into histograms and records the proportion (fraction) of observations in each histogram. - It groups data into intervals called classes and records the proportion (fraction) of observations in each class. - It groups data into intervals called classes and records the number of observations in each class. - It groups data into categories and records the number of observations in each category.

It groups data into categories and records the number of observations in each category.

The owner of a company has recently decided to raise the salary of one employee, who was already making the highest salary, by 20%. Which of the following is(are) expected to be affected by this raise? - Mean only - Median only - Mean and median only - Mean, median, and mode

Mean only

What does the covariance measure?

The direction of a linear relationship between two variables.

Which of the following statements is not true? - Bar charts focus the attention on the frequency of the occurrences of the categories. - The height of each rectangle in a bar chart equals the width of the rectangle for each category. - A bar chart is created by drawing a rectangle representing each category. - all of these choices

The height of each rectangle in a bar chart equals the width of the rectangle for each category.

Which of the following is not a characteristic of graphical excellence? - The ideas and concepts the statistician wants to deliver are clearly misunderstood by the viewer of the graph. - The graph presents large data sets concisely and coherently while small data sets are easily presented in tabular form - The graph induces the viewer to address substance of the data and not the form of the graph - The graph encourages the viewer to compare two or more variables to depict relationships between the variables or to explain how and why the observed results occurred. .

The ideas and concepts the statistician wants to deliver are clearly misunderstood by the viewer of the graph.

A category that contains 40% of the observations is represented by a slice of a pie chart that contains 144 degrees

True

For quantitative data, a cumulative relative frequency distribution records the proportion (fraction) of values that fall below the upper limit of each class.

True

Mark's grade on the recent business statistics test was an 85 on a scale of 0-100. Based on this information we cannot conclude that Mark's grade was in the 85th percentile in his class.

True

The branch of statistical studies called descriptive statistics summarizes important aspects of a data set.

True

The relative frequency of a category is calculated by dividing the category's frequency by the total number of observations.

True

The variance and standard deviation are not the most widely used measures of central location.

True

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

Variance and standard deviation

The coefficient of variation is best described as ___________________________________.

a relative measure of dispersion