Data Analytics

Study Guide: An Introduction to Descriptive Statistics

Definition of Descriptive Statistics

• Descriptive Statistics are summary statistics that quantitatively describe or summarize features of a dataset.

• They provide simple summaries about the sample and the measures.

Key Concepts

1. Measures of Central Tendency:

   • Mean: The average of a set of values.

   • Median: The middle value of a data set when it is ordered.

   • Mode: The value that appears most frequently in a data set.

2. Measures of Dispersion:

   • Range: The difference between the highest and lowest values.

   • Variance: A measure of how far each number in the dataset is from the mean.

   • Standard Deviation: The square root of the variance, indicating how much the data varies from the mean.

3. Data Visualization:

   • Histograms: A graphical representation of the distribution of numerical data.

   • Box Plots: A standardized way of displaying the distribution of data based on a five-number summary.

   • Scatter Plots: A plot that shows the relationship between two quantitative variables.

Importance of Descriptive Statistics

• Helps in understanding trends, patterns, and anomalies within the data.

• Useful for giving a quick overview of the data set before conducting further analyses.

• Aids in making informed decisions based on the summarized data.