Basics of Statistics
This is the entire group a study is intended to describe.
What is a population?
This type of study observes subjects without applying a treatment.
What is an observational study?
This graph is most appropriate for displaying categorical data.
What is a bar graph?
This measure of center represents the middle value of an ordered data set.
What is the median?
This type of distribution is symmetric and bell‑shaped.
What is a normal distribution?
This numerical value is calculated from sample data.
What is a statistic?
This type of study applies a treatment and compares results.
What is an experiment?
This type of graph displays quantitative data grouped into equal intervals.
What is a histogram?
This measure is found by subtracting the minimum value from the maximum value.
What is the range?
This value tells how many standard deviations a data point is from the mean.
What is a z‑score?
This type of data classifies individuals into groups such as eye color or brand of phone.
What is categorical data?
This variable interferes with determining whether a treatment caused an outcome.
What is a confounding variable?
This distortion occurs when a graph’s vertical axis does not start at zero.
What is baseline distortion?
This measure describes how far data values typically are from the mean.
What is standard deviation?
About 68% of data fall within this many standard deviations of the mean.
What is 1 standard deviation?
This occurs when a sample does not accurately represent the population being studied.
What is sampling bias?
This psychological effect occurs when subjects improve simply because they believe they received treatment.
What is the placebo effect?
This visual display can exaggerate differences if image size is scaled in more than one dimension.
What is a pictogram?
This summary includes the minimum, quartiles, and maximum.
What is the five‑number summary?
Being in the 90th percentile means scoring higher than this percentage of the population.
What is 90%?
A large sample can still give misleading results if this problem exists.
What is bias in sampling?
This type of study compares two existing groups and is often used when experiments are unethical.
What is a case‑control study?
These must be equal in size to ensure a histogram fairly represents data.
What are class intervals (bins)?
This graph uses a five‑number summary to compare data sets visually.
What is a box plot?
A test score has a z‑score of 2. Explain what this means about the score’s position in the distribution.
What is “the score is 2 standard deviations above the mean”?