Quantitative Reasoning Course for BS Honours Level Students Definition and Scope of Statistics Statistics is the branch of mathematics that deals with the collection, analysis, interpretation, presentation, and organisation of data. It provides tools and methods to make sense of numerical information, identify patterns, draw inferences, and make informed decisions under uncertainty. The scope of statistics is broad and interdisciplinary: Descriptive Statistics : Summarises and describes the features of a dataset, such as calculating means, medians, or creating charts to visualise data. Inferential Statistics : Uses sample data to make generalisations or predictions about a larger population, often involving hypothesis testing, confidence intervals, and regression analysis. Applied Fields : Extends to economics (e.g., forecasting trends), biology (e.g., clinical trials), social sciences (e.g., surveys), engineering (e.g., quality control), and data science (e.g., machine learning m...
Measures of Central Tendency Measures of central tendency are the specific statistical values which describe the typical values or central position of a dataset. The three most common single statistical values include Mean, Median and Mode. Arithmetic Mean : Average of all values (sum divided by count). Geometric Mean : nth root of the product of values (used for growth rates). Harmonic Mean : The Reciprocal of the average of reciprocals (used for rates like speed). Median : Middle value when data is ordered. Quartiles : Values dividing data into four equal parts (Q1=25th, Q2=50th=median, Q3=75th percentile). Mode : Most frequent value. Measures of Dispersion Range : Difference between maximum and minimum values. Quartile Deviation : Half the interquartile range (Q3 - Q1)/2. Mean Deviation : Average absolute deviation from the mean. Variance : Average squared deviation from the mean. Standard Deviation : Square root of variance (spread in original units). Coefficient of Varia...