 Descriptive Statistics: Covariance

One way of checking the relationship between two variables is with covariance. This gives an indication if the two variables are correlated, one to another. A related post is that of Dispersion and Variance: Population Covariance The formula for population covariance is: Sample Covariance If the covariance value (between variables) Continue Reading Measures of Asymmetry

Building off the article below, I wanted to continue this discussion dealing with Right and Left Skewness. Specifically, how to calculate this in Python or visualize Asymmetry issues in Python. Skewness Right skewness is when the the Mean is Larger than the Median. The tail is longer towards the right Continue Reading Bar and Scatter Plots

In the above code, I’ve got a data frame of some fake car data. I have five cars, with column values for Top Speed, Price, MPG and Deaths per Year. To plot this as a bar graph, we can combine the column data into one plot using Pandas: I’ve not Continue Reading Descriptive Statistics: Cross Tables with Python

In a previous post, Frequency Distribution tables were briefly discussed. In this post, I’m going to quickly show how to build a cross table in Python Pandas. Cross Tables Unlike a spreadsheet where each row is an observation, a cross tab (or cross table) gives a tally of multiple variables. Continue Reading Plotting a Histogram

In a previous post about Frequency Distribution tables, a lot of pre-work was done to setup a set of frequency distribution and relative frequency distribution into tabular form. This time, I’ll take the same data set used, and plot a histogram to visually notice the frequency distribution. Unlike tabular data, Continue Reading Descriptive Statistics: Frequency Distribution Table

A frequency distribution table is much like a spreadsheet. This is where we have One Way Data being represented in a table form. Figure 1 above shows a frequency distribution table. Specifically it shows a tally of suicides per year by country. Each row is an observation and each column Continue Reading

Bayes Theorem

For this post I’m going to cite several different explanations, as Bayes Theorem always trips me up. The idea behind Bayes Theorem, is that it’s a form of conditional probability. In other words, what’s the probability of Event A occurring, given that Event B has occurred? Krista King: Bayes Theorem Continue Reading

Combinations

Combinations are sets of objects that are unordered. Permutations were concerned with order. In a permutation the values 1234, 2341, 3412 and 4321 are treated as different. However, in Combinations, they are treated as 1 result. If you’re curious about the Latex Markdown to create the equation above, it is Continue Reading

Permutations

A permutation is a calculation of how many ways a set can be represented. This is a simple factorial of the number of the entire set. Meaning if we had a set of values: However the formula changes as we get into more complex problems. Consider this example on BetterExplained.com: Continue Reading

Probability Question

Taken from the Udemy course Probability & Statistics for Business and Data Science. Consider the following question: “A company made a total of 50 trumpet valves. It is determined that one of the values (of 50) was defective. If three valves are used in a trumpet, what is the probability Continue Reading