For you to make appropriate correlation calculation, it is important to have two different columns. It makes it easier to know if there is any correlation between them. We are going to use unit price and quantity of sold units to determine if there is any correlation between them.
Layout the columns, we have chosen unit price and sold units for this calculation.
Click on an empty column on the unit sold (1), and type in =CORREL(columns that are relevant to the columns ex. A1:A4, B1:B3), which is number 2 in the picture below.
Now you can create correlation chart based on above correlation data..
Further reading: How to calculate covariance?