My Notes

Author: Tom

  • 3 Measures of central tendency

    Mean/Simple Average The mean is simple average of the dataset and it is denoted by Mean = (x1+x2+x3+….+xN)/N Mean is the most commonly used measure of central tendency the downside is it is easily affected by the outliers in the dataset Mean can be termed as Center of gravity of the given data. Median The…

  • Cross tables and Scatter Plots

    Cross tables and scatterplots are used to represent relations between more than one variables. We use Cross tables for categorical variables and scatter plots for numerical variables. Cross Tables Type of investment \ Investor Investor A Investor B Investor C Total Stocks 96 185 39 320 Bonds 181 3 29 213 Real Estate 88 152…

  • Histogram

    Histogram is the most common graph used to represent numerical data. Histogram looks similar to a bar chart but is very different. In a bar chart, only the vertical axis represents numerical data(absolute frequency) but in Histogram, both the vertical and horizontal axis represents numerical data. Each bar in a histogram has a width equal…

  • Numerical Variables: Frequency Distribution

    Usually, numerical variables by default will have a frequency of 1 most of the time making the frequency table impractical for any analysis. Dataset Frequency 1 1 9 1 22 1 24 1 32 1 41 1 44 1 48 1 57 1 66 1 70 1 73 1 75 1 76 1 79 1…

  • Categorical Variables: Visualization Techniques

    Some of the common ways to visualize categorical variables: Frequency Distribution Table: Brand Frequency Brand A 84 Brand B 67 Brand C 102 Total 253 Bar Chart: Bar charts are useful to visually compare items/groups among each other based on their frequency Pie Chart: Pie charts are useful when we not only want to compare…

  • Types of Data & Levels of Measurement

    Data can be classified in two main ways: Based on the type of data and measurement level. Types of Data: Levels of Measurement:

  • Population vs Sample

    Population Sample Samples are key to accurate statistical insights. A Sample must be both Random and Representative for an accurate statistical insight. Randomness: A random sample is collected when each member of the sample is chosen from the population strictly by chance Representativeness: A Representative sample is a subset of the population that accurately reflects…