Category: Statistics

Skewness in Excel

Skewness is a measurement which helps you to understand the effect outliers are having in your data.   A positive skewness indicates a ‘right-skewed’ distribution where the majority of the values are on the left of the distribution and the outlier values are on the right. A negative skewness indicates the opposite. If a skewness Read More …

Data Science Terms & Technology

DATA MINING Data mining The technology used for collecting, store, processing, transforming and analysing raw data in order to make it useful for gaining insights.     Knowledge Discovery KDD stands for Knowledge Discovery in Databases, which covers the creation of knowledge from structured and unstructured sources in an attempt to formalise the knowledge discovery Read More …

Analysis

SIGNIFICANCE TESTING Hypothesis A prediction or statement about a characteristic of a variable, which can be tested to provide evidence for or against.     Significance test A method of statistically testing a hypothesis by comparing data against values predicted by the hypothesis. The significance test considers two hypotheses, the null and the alternative, effectively Read More …

Mathematics

CALCULATIONS Mode The most common value for a variable based on its frequency, can be calculated from either qualitative or quantitative data. The MODE function can be used in Excel to return this.     Mean The average value based on a variable of quantitative data.   The arithmetic mean is the most commonly used. Read More …

Statistics

VARIABLES Qualitative vs Quantitative variables Qualitative variables are categorical items, whereas quantitative variables have a numerical value associated.Qualitative example: Blood groupQuantitative example: Temperature     Discrete vs Continuous variables Quantitative variables can be split into discrete (counted to an exact figure) or continuous, which can’t be measured precisely so need to be rounded.Discrete example: No Read More …