Chapter 1

Two common ways of displaying categorical data is column charts and pie charts.

True

A variable is classified as ordinal if

there is a natural ordering of categories

The daily closing values of the Dow Jones Industrial Average over a period of 30 days are best described as _____ data.

time-series

Cross-sectional data are data on a population at a distinct point in time, whereas time series data are data collected over time

True

A histogram that is positively skewed may also be described as

skewed to the right.

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.

Difference between categorical and quantitative variables.

Categorical: based on qualitative data. Ex: car model, birth yr, zip code. Quantitative: measurements/observations taken on numerical values. Ex: GPA, height, weight, number of textbooks

What are the qualities of nominal scale?

Data are labels or names used to identify an attribute of the element. Can use nonnumerical label or numerical code ex: students classified by label like "arts" "math" or they can have 1-arts 2-math

What are the qualities of ratio scale?

Data have all the properties of interval data and the ratio of two values is meaningful. ALWAYS numeric and zero value is included in scale. ex: book sold for $100 online is $200 in store. The store charges 2X as much as online.

What is the difference between numerical discrete and numerical continuous data?

Discrete: Isolated points on a number line; whole numbers (ex: number of people) Continuous: Can be any value in a given interval; usually measurements (ex: GPAs)

A data set is typically a rectangular array of data, with observations in columns and variables in row

False

All nominal data may be treated as ordinal data.

False

Categorical variables can be classified as either discrete or continuous.

False

Phone numbers, Social Security numbers, and zip codes are typically treated as numerical variables

False

What is the most common type of chart for showing the distribution of a numerical variable?

Histogram

What are the 5 qualities you can comment on about a histogram?

Spread, skewness, center, outliers, modal (uni/bi/milt)

What are the qualities of ordinal scale?

The data have the properties of nominal data and the order or rank of data is meaningful Ex: students classified by standing using "freshman" "sophomore" or a code could be used like 1-freshamn 2-sophmore

What are the qualities of interval scale?

The data have the properties of ordinal, and the interval between observations is expressed in terms of a fixed unit of measure. ALWAYS numeric ex: Melissa has SAT score of 1985 and Kevin has score of 1880. Melissa scored 105 more than Kevin

A variable (or field or attribute) is a characteristic of members of a population, whereas an observation (or case or record) is a list of all variable values for a single member of a population.

True

Both ordinal and nominal variables are categorical

True

Categorizing a numeric age variable as "young," "middle-aged," and "elderly" is an example of

binning

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

descriptive statistics.

Data that arise from counts are best described as _____ data.

discrete

Coding males as 1 and females as 0 in a data set illustrates the use of _____ variables

dummy