UARK Data Analysis Exam 1

descriptive statistics

includes charts and graphs and studies values directly

inferential statistics

making predictions and draw conclusions that go beyond what the numbers directly indicate

Ratio Data

an ordered scale that includes a zero point

ordinal

being of a specified position or order in a numbered series (ex. letter grade)

Numerical Data Types

Quantitative, Ratio, Interval

Categorical Data Types

Qualitative, Nominal, Ordinal

Quantitative Data

Data associated with mathematical models and statistical techniques used to analyze spatial location and association.

Interval Data

Differences between values can be found, but there is no absolute 0. (Temperature, Time, # of students in a class)

Qualitative Data

Information describing color, odor, shape, or some other physical characteristic

Nominal Data

data of categories only. Data cannot be arranged in an ordering scheme. (Gender, Race, Religion) (Defined Categories)

Ordinal Data

A statistical data type where the exact numerical value has no significance other than to rank a set of data points. Deals with the order or position of items (ordered categories)

Discrete Data

data in which the number CANNOT be cut in half (counted items)

Continuous data

data in which the number CAN be cut in half (measured characteristics)

Causality

the notion that a change in one factor results in a corresponding change in another

confounding/lurking variable

a variable other than the independent variable that you are interested in

independent variable (explanatory variable)

the variable that you change

Dependent Variable (Responding Variable)

the variable affected by the independent variable

interval scale

ordered scale in which the difference between measurements is a meaningful quantity, but they do not have a true zero point (ex. Temp or ACT score)

ratio scale

an ordered scale in which the difference between the measurements is a meaningful quantity and the measurements have a true zero point (ex. Age, Weight, Salary)

simple random sampling

every member of the population has a known and equal chance of selection

systematic sampling

A procedure in which the selected sampling units are spaced regularly throughout the population; that is, every n'th unit is selected.

stratified sampling

a variation of random sampling; the population is divided into subgroups

cluster sample

obtained by selecting all individuals within a randomly selected collection or group of individuals

This chart is best used for ranking

bar chart

This chart is best used for part-to-whole measurements. (percentages, ratio to the whole)

pie chart

This chart is best used for measuring frequencies of categories

frequency count

histogram

A graph of vertical bars representing the frequency distribution of a set of data. (numerical data)

This chart is best used for time series data

line chart

This chart is best used for exploring relations between 2 numerical variables

scatter plot

central tendency

the extent to which all the data values group around a typical or central value

variation

the amount of dispersion or scattering away from a central value that the values of a numerical variable show

shape

the pattern of the distribution of values from the lowest value to the highest value

Skewness

measures the extent to which data values are not symmetrical

Kurtosis

measures how sharply the curve rises approaching the center of distribution