Problem: Using PCA study similarities in stock behaviour In this example we will use stock prices of 9 companies from Jan 2015 to Mar 2023. Four of the companies belong to the Tech sector and four belong to the Financial sector. There is one company which is unknown. We will use PCA to analyse these stocks and guess the sector to which the unknown company belongs to. The data is given in stocks.csv which we import as a data frame using pandas. This dataframe has 2052 rows and 9 columns. Since we are intersted in trends rather than actual stock prices, the data is converted to percent change using .pct_change(). This is common practice when looking for trends in time series data.