What is Statistics?
The art and science of answering questions and exploring ideas through the processes of
gathering data, describing data, and making generalizations about a population on the
basis of a smaller sample.
What is a variable?
Characteristic of units that can take on different values (in other words, something that can
vary).
What is a unit?
The basic objects on which the data is collected.
What is a categorical variable?
A variable with values that can’t be quantifiable.
What is a nominal categorical variable?
Describes a name, label or category without a logical order (e.g., gender)
What is an ordinal categorical variable?
A categorical variable, whose values are defined by an order between the different categories (e.g.,
education level).
What are quantitative variables?
Variables that have numerical values with magnitudes that can be placed in a meaningful order with consistent intervals, also known as numerical.
What are discrete variables?
Variables that can only take on a set number of values (e.g., only whole numbers)
What are continuous variables?
Variables that can take on any value and any value between values (e.g., out to an infinite number of decimal places)
What is a population?
The entire set of individuals, objects, events, or data points that share at least one common characteristic and are of interest to a researcher
What is a sample?
A smaller subset of the population
What are sample statistics?
Values concerning a sample
What is a population parameter?
A value concerning a population.
What is sampling bias?
Systematic favoring of certain outcomes due to the methods employed to obtain the sample.
What is simple random sampling?
A method of obtaining a sample from a population in which every member of the population has an equal chance of being selected.
What are central tendency measures?
*Quantitative variables are often summarized using numbers to communicate their central tendency.
* The mean and median are two of the most commonly used measures of central tendency.
What is the Mean?
The numerical average; calculated as the sum of all of the data values divided by the number of values.
What is the sign for sample mean?
x-bar
What is the sign for population mean?
µ (mu)
What is the Median?
The middle of the distribution that has been ordered from smallest to largest; for distributions with an even number of values, this is the mean of the two middle values.
What are variability measures?
Variability measures describe “data spread” or how far away the measurements are from the center.
What is the Standard Deviation?
Roughly the average difference between individual data values and the mean.
What is the sign for sample SD?
s
What is the sign for population SD?
σ (sigma)
