Statistics Review Notes

These flashcards cover essential concepts related to statistics, including measures of central tendency, variability, correlation, and regression analysis.

What is a contingency table used for?

To display the frequency distribution of two categorical variables.

What does the five-number summary include?

Minimum, Q1 (lower quartile), median, Q3 (upper quartile), and maximum.

What is the formula for calculating the z-score?

z = (X - mean) / standard deviation.

What does a boxplot visually summarize?

The five-number summary and outliers of a data set.

What is the significance of the IQR?

The IQR (interquartile range) is a measure of statistical dispersion and is resistant to outliers.

Define skewness in distributions.

Skewness indicates the direction and degree of asymmetry of a distribution.

What are outliers?

Extreme values that differ significantly from other observations in a dataset.

How do you find the range of a dataset?

Range is calculated as max - min.

What does the coefficient of determination (R²) indicate?

The proportion of the variance in the dependent variable that is predictable from the independent variable(s).

What are z-scores used for in statistics?

To measure the standard deviations away from the mean.

What information does the correlation coefficient (r) provide?

The strength and direction of a linear relationship between two variables.

What does a negative correlation indicate?

As one variable increases, the other variable tends to decrease.

What is the 68-95-99.7 rule?

In a normal distribution, approximately 68% of values fall within one standard deviation, 95% fall within two, and 99.7% fall within three standard deviations from the mean.

How can you determine whether to use mean or median?

Use mean for symmetric distributions and median for skewed distributions.

What is linear regression used for?

To predict the value of one variable based on the value of another variable.

What does 'sensitive to outliers' mean for standard deviation and range?

Values can be significantly affected by extreme data points.

What is a lurking variable?

A variable that is not included in the analysis but affects both the independent and dependent variables.