DC-Den

I covered a number of statistical tests using Excel LAMBDA. The reason for using Excel LAMBDA was its ubiquity and undemanding learning curve . While there are more statistical inferences test, I only covered those that I commonly used. If however you think other common ones, please let me know. I would be interested as well. Data Mining or Machine Learning When I started data analysis, the term data mining made sense. The techniques used within Data Mining is with the intention of identifying patterns within a data set. The problem came when I started searching more of a topic from data mining, they keep popping up in  machine learning . Machine Learning  is the process of computers learning in a way that mimics human learning or through algorithms. To accomplish this machine learning use data mining techniques as the process requires identification of patterns. While there is a difference between data mining and machine learning, do not be surprise of the overlap or if you start wond

Recently I wanted to find the correlation coefficient between multiple groups of data. A correlation coefficient shows the relationship between two groups of data . A positive correlation means as one variable increase the other increases, while a negative correlation means as one variable increases the other variable decreases. The correlation of variable with itself is always 1. A zero correlation indicates no relationship. Correlation coefficient is always between -1 and 1. Positive, Zero and Negative Correlation Excel provides the CORREL  function for this. It is fairly easy to use as shown by its syntax: CORREL(array1, array2) A correlation matrix is a table showing the correlation between pairs of variables . You could put the coefficients in a table like the one shown below. Implementing a Correlation Matrix function I thought of using LAMBDA instead. Such correlation matrix would be n x n table, where n is the number of data groups; number of columns from the d

Camel Case   Snake Case There are a few syntax styles among programmers. I mentioned snake and camel case previously. Here are a few of the different notations: snake_case_notation cameCaseNotation PascalCaseNotation nocasenotation kebab-case-notation Excel LAMBDA is not case sensitive. So while you don't have to use these notations, without them code reading becomes difficult. I also recommend keeping Excel native functions in upper case. e.g. SUM, AVERAGE, COUNT . This to distinguish Excel functions from your own functions and variables.  Snake Case Notation I used snake case notation in Excel LAMBDA because LAMBDA didn't have an IDE (yet!) and I was writing the functions in a plain text editor. Snake case notation is easy to read as the individual words are spaced out. grp_sum, BYCOL(array, LAMBDA(p_column, SUM(p_column))), my_var, long_function_name(array), Camel Case Notation I switched to camel case notation when I started implementing data m