Author: whizzexcel@gmail.com

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

SOFTWARE Microsoft Azure Machine Learning Studio A drag-and-drop tool with a graphical user interface for building, testing and deploying predictive analytics solutions on your data.   SAS Enterprise Miner A solution for creating accurate predictive and descriptive data models using data mining and statistical techniques such as linear regression, clustering and classification (decision trees).   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 testing 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.   Mean The average value based on a variable of quantitative data.   Median The central value of a variable of quantitative data. Using the median instead of the mean lessens the impact Read More …

Basic 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 of Read More …

Refresh one connection at a time

In some cases you might find that the RefreshAll command isn’t working as you’d hoped. For example, if you have a pivot table looking up data from a SQL database connection you need the pivot table to refresh after the connection but RefreshAll won’t necessarily do that.   To ensure one connection is refreshed at Read More …