Descriptive Statistics Summary

These flashcards cover key concepts from descriptive statistics, including measures of center, variability, and graphical data representation.

What does 'N' represent in statistics?

'N' represents the population size.

What does 'n' represent in statistics?

'n' represents the sample size.

How do you calculate the mean of a data set?

The mean is calculated by summing all the values and dividing by the number of values, expressed as μ = Σxi / N.

What is the median?

The median is the middle value in a sorted data set.

What is a robust estimator?

A robust estimator is not drastically influenced by outliers.

What does a symmetric distribution imply about the mean and median?

In a symmetric distribution, the mean and median are the same.

What happens to the mean and median in a right-skewed distribution?

In a right-skewed distribution, the mean is greater than the median.

What is the formula for variance in a population?

Variance in a population is calculated as σ² = Σ (X - μ)² / N.

What is the Empirical Rule?

The Empirical Rule states that for a normal distribution, approximately 68% of values fall within one standard deviation, 95% within two, and 99.7% within three standard deviations of the mean.

What are quartiles?

Quartiles are values that divide a data set into four equal parts.

What is the Interquartile Range (IQR)?

The IQR is the difference between the first quartile (Q1) and the third quartile (Q3).

How is a boxplot structured?

A boxplot displays the distribution of a data set using five summary statistics: minimum, first quartile, median, third quartile, and maximum.

What do Z-scores indicate?

Z-scores indicate how many standard deviations a data point is from the mean.

What should you use if outliers are present in the data set?

If outliers are present, it's better to use the median instead of the mean.

What is the purpose of comparing relative variability?

Comparing relative variability allows assessment of variability across different populations or data sets.