Data & Sampling
This variable has no natural order.
What is a nominal variable?
The only kind of study which can determine cause and effect.
What is an experimental study?
The difference between consecutive class limits.
What is the class width?
Also known as the average, obtained by adding all data points and dividing by the number of items.
What is the mean?
A common way of saying that just because things happen together doesn't mean they are related.
This variable's categories have a natural order.
What are ordinal variables?
This sampling method is based on ease of access to individuals.
What is a sample of convenience?
The data has a "tail" and is unequally distributed.
What is a skew?
A high point of the data, usually limited to one or two in any sample.
What is the mode?
Data that consist of ordered pairs.
What are bivariate data?
This data is counted.
What is discrete data?
The gold standard for reliable, accurate data.
What is a simple random sample?
This expresses a frequency distribution in the form of a percentage.
What is a relative frequency?
The 50th quartile of data.
What is the median?
A number between 1 and -1 which measures the strength of a linear relationship.
What is the correlation coefficient, r?
This data has no quantity and must be arranged by its properties, such as color, location or alphabetization.
What is a qualitative variable?
A study in which people are simply watched.
What is an observation study?
A histogram in which bars are ordered by size.
What is a Pareto chart?
Found by subtracting Q1 from Q3 (Q3-Q1).
What is the interquartile range?
When plotted, the data clusters around a straight line.
What is a linear relationship?
Every nth item is sampled.
What is systematic sampling?
This bias will subconsciously influence researchers to alter the results for their own benefit.
What is self-interest bias?
A polygon graph illustrating the cumulative frequencies.
What is an ogive?
The amount of data which can be found within 1 standard deviation in either direction from the mean.
What is 68%?
A line where the sum of the squared distances is as small as possible.
What is the least-squares regression line?
The data is divided into categories; then, random samples are taken from each one.
What is stratified sampling?
This bias is created because some individuals don't reply.
What is nonresponse bias?
A plot where the data measures different points in time.
What is a time-series plot?
A single horizontal line drawn from the third quartile to the largest data point inside the outlier boundary.
What is a whisker?
The sum of the explained variation plus the unexplained variation.
What is the total variation?