Question 1

How often do I use my credit card each month?

Note that it’s not how much I used my credit card from Oct 2020 to Oct 2021. It varies month to month but it’s about 30 transactions. That means I made a credit card transaction at least one per day.

But towards the end of 2021, I switched to a different credit card so the transaction volumen went down significantly. With the table, it is easier to navigate when and how much I spent for each transaction.

Question 2

Which category did I spend the most?

I spent the most money on grocery shopping. This makes sense because the period between Oct 2020 and Oct 2021 was the peak of COVID-19 pandemic. So I couldn’t go out and eat at restaurants or travel abroad for a long period of time.

Also, it’s worth mentioning that because of the pandmeic, I spent more time and money while I was browsing on the web. Around this time, I also got rid of my car so the automotive cost went down significantly.

Question 3

Does transactions (month-year) predict amount?

As we can see from the boxplot, it is hard to say we can predict how much I would spend each month. But with the data, we can get a median ($16.63) and average ($42.92) amount for each transaction.

From question 1, we figure out that I do 30 transactions per month. So we take the media of each transaction and multiply it by 30, we get about $489.90.

If we take the average and multiply by 30, then we get about $1,287. That said, we may conclude the spending can be range from $490 and $1,300 per month. This fits with my current recurring credit card bills which is usually around $1,000 (excluding rent payments, of course).

Question 4

Compare shopping and groceries expenses, is there any interesting pattern?

Spending habits vary a little bit depending on each category. While it occasionally changes to “0,” it rarely does so for groceries. This is a somewhat accurate statement that I went grocery shopping at least once per week. I also spent a lot more money on groceries than I normally would due to the pandemic lockdown.

Contrarily, I find that shopping is more interesting than my pattern of grocery expenditure. If you look at the shopping graph, it appears that I didn’t spend much money for a few months, but then it spikes up, indicating that I spent a lot of money at irregular intervals.

Why does this matter? The cost of grocery shopping is typically fixed. The food is always just me eating it, unless I have a child. However, shopping is done time to time. And my needs change, and often I buy stuff for other people. So it’s more complicated than grocery shopping.

And this leads to my last question: What about others?

Question 5

How was my spending habit in each category? Any interesting relationship?

Compared to shopping, fixed costs like groceries generally don’t fluctuate as much. It’s also fascinating to note that the majority of my spending was on food, either for my body or for my intellect. This is logical. Because of the pandemic lockdown, I put a lot of effort into completing classes and attending lectures online. Since I couldn’t go out to dine like I had done for groceries, I purchased everything from Trader Joe’s in quantity.

That came to roughly “1/3” of what I spent between October 2020 and October 2021. Also note that I was living with my ex-girlfriend’s family at this time. I therefore chose to pay the family’s grocery expenditures rather than the rent, even though it was not required. In the end, I didn’t save as much money as I had hoped to save. But I had a great time with them over lunches and dinners. So it was money worth spent.