I am trying to check if there is a correlation between spam emails and weekdays. My dataset looks like as follows:

  Spam? Day
0   1.0 Saturday
1   1.0 Saturday
3   0.0 Saturday
5   1.0 Saturday
7   0.0 Friday
... ... ...
346 0.0 Friday
348 1.0 Friday
361 0.0 Saturday
383 1.0 Thursday
387 1.0 Friday

where 1 means spam and 0 not spam.

I have tried as follows

corr = (numpy.corrcoef(df['Spam?'],df['Days']))

I do not know how to explain a possible relationship between these two variables and if a plot could help to better visualise data and relationship.

  • 1
    $\begingroup$ Do you mean to see if there is a difference between volume of spam received on weekdays compared to the weekend? $\endgroup$
    – Dave
    Sep 11, 2020 at 19:58
  • $\begingroup$ yes, I am trying to analyse some aspect of sending spam, trying to understand what could be interesting to be investigated. So I wanted determine if there is a correlation between the volume of spam received on weekdays compared to the weekend. But other type of suggestions would be greatly appreciated it $\endgroup$
    – LdM
    Sep 11, 2020 at 22:03

2 Answers 2


(started as a comment but it turned out to be longer than expected)

With a dataset like this a simple barplot could be very insightful: on the X axis the days of the week, on the Y axis the frequency, with two bars (spam/not spam using different color) for each day. A slightly more advanced version: two boxplots, one for weekdays the other for weekends. A boxplot is kind of overkill for only 5 (mon-fri) and 2 (sat-sun) values but it's easy to do and shows the big picture.

In order to test whether any difference (e.g. weekdays vs weekends) is significant I think this is a good case for a chi square test.


numpy.corrcoef will gives you Pearson Correlation but your Features are Categorical.
You should calculate Crammer'v.

You can get details/code in this answer as both the questions are a bit similar DS.SE

On Plot
What Erwan has suggested seems good.
Also, try to plot(line-plot) between days-of-week and spam/total ratio(i.e. Stanardizing for total volume) since a single figure is easier to comprehend.

  • $\begingroup$ thanks for your answer 10xAl $\endgroup$
    – LdM
    Sep 13, 2020 at 2:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.