Descriptive Statistics

 What is Descriptive Statistics?

Descriptive statistics is a branch of statistics that focuses on summarizing and describing the main features of a dataset or population. It involves organizing, analyzing, and presenting data in a meaningful way to gain insights and understand the underlying patterns or characteristics of the data.

Most Common Descriptive Statistics:

• Measures of Central Tendency:

• Mean: The average value of a dataset. It is calculated by summing all the values and dividing by the number of observations.
• Median: The middle value in a dataset when it is arranged in ascending or descending order. It is less sensitive to extreme values than the mean.
• Mode: The most frequently occurring value(s) in a dataset.

• Measures of Variability:

• Range: The difference between the maximum and minimum values in a dataset. It gives an idea of the spread of the data.
• Variance: The average squared deviation from the mean. It quantifies the dispersion of data points from the mean.
• Standard Deviation: The square root of the variance. It measures the average distance between each data point and the mean.

• Percentiles and Quartiles:

• Percentiles: Values that divide a dataset into hundredths. For example, the 75th percentile represents the value below which 75% of the data falls.
• Quartiles: Values that divide a dataset into quarters. The first quartile (Q1) represents the 25th percentile, the median (Q2) represents the 50th percentile, and the third quartile (Q3) represents the 75th percentile.

• Skewness and Kurtosis:

• Skewness: A measure of the asymmetry of the distribution. Positive skewness indicates a longer tail on the right side, while negative skewness indicates a longer tail on the left side.
• Kurtosis: A measure of the peakedness or flatness of the distribution. It assesses whether the data has heavier or lighter tails compared to a normal distribution.

• Frequency Distribution and Histograms:

• Frequency Distribution: A table or graph that shows the count or proportion of values falling into different intervals or categories.
• Histogram: A graphical representation of the frequency distribution, where the data is divided into bins or intervals and displayed as bars.

• Correlation

  Coefficient: A measure that quantifies the strength and direction of the linear relationship between two variables. Commonly used correlation coefficients include Pearson's correlation coefficient and Spearman's rank correlation coefficient.

Descriptive statistics provide a snapshot of the data and allow researchers, analysts, and decision-makers to understand and communicate key characteristics of a dataset without making inferences or generalizations about a larger population.