Statistics Review

Flashcards for reviewing key statistical concepts.

Statistics

The science of collecting, organizing, analyzing, and interpreting data.

Descriptive Statistics

To describe the variables and summarize data in a meaningful way.

Inferential Statistics

Allows you to make inferences or predictions using your data; Used to test hypotheses.

Levels of Measurement

Categorizing research data into four levels, forming a hierarchy that helps determine applicable statistical formulas.

Nominal Data

Represents a set of labels that cannot be quantified, calculated, or placed in ascending/descending order.

Ordinal Data

Data that can be labeled and ranked from highest to lowest, allowing for arrangement in order but lacking equal intervals between ranks.

Interval Data

Data that can be labeled, ranked, with equal intervals between scores, but lacks an absolute zero value.

Ratio Data

The most flexible data type, combining nominal, ordinal, and interval features with an absolute zero, allowing for all mathematical operations.

Distribution

The range of values of a variable according to their frequency.

Normal Distribution

A distribution that visually looks like a bell curve or Gaussian curve, where data points cluster in the middle with few scores in the extremes.

Outliers

Data points that cause a data set to deviate from normality.

Measures of Central Tendency

Tell you the central score or common score in your data.

Mean

The average of all scores, computed by adding all data points and dividing by the number of observations.

Median

The middle score or midway point when data is arranged in order.

Mode

The value that appears most often in the data or distribution.

Measures of Dispersion

Tell you how spread out the data points are around the center, measuring the variability of the items themselves and the variation around the average.

Standard Deviation

Measures the amount of variation or dispersion of a set of values around the mean.

Semi-Interquartile Range (SIR)

An alternative measure of dispersion used if the distribution deviates from normality or the level of measurement is at least ordinal, based on quartiles.

Quartiles

Values that divide data into quarters after arranging it in ascending order.

Variance

The square root of the variance, widely used because it is expressed in the same units as the data, making interpretation easier.

Z-score

The number of standard deviations from the mean a data point is.

Confidence Interval

A specified range of values within which a population parameter is estimated to lie.

A basic measure of probability, indicating how likely an event is

Independent Variable

The variable that is manipulated or changed by the researcher to observe its effects on the dependent variable.

Dependent Variable

The variable that is measured or tested in an experiment.

P-value

The probability of obtaining results as extreme as the ones observed, assuming that the null hypothesis is correct.

Null Hypothesis

A statement that assumes there is no significant difference or relationship between variables.

Alternative Hypothesis

A statement that contradicts the null hypothesis, suggesting that there is a significant difference or relationship between variables.