Data analysis involves collecting, organizing, and interpreting information to draw meaningful conclusions. Descriptive statistics summarize data using measures of central tendency and measures of spread.
The mean is the arithmetic average — sum all values and divide by the count. The median is the middle value when data is ordered. The mode is the most frequently occurring value. Each measure captures a different aspect of the data's center.
The range is the difference between the maximum and minimum values. Variance measures the average squared deviation from the mean. Standard deviation is the square root of variance, bringing the measure back to the original units.
Data can be displayed using histograms, box plots, scatter plots, and bar charts. Each visualization reveals different patterns: distributions, outliers, correlations, and trends over time.