imputed missing values in the 'Amount' column

[DonJoseph1]

Key findings:

• For negative merchant transactions, providing there are enough transactions - these can be imputed by mean.
• If there are too few of these transactions - then it should be imputed by mean of the overall merchant spending distribution. As these are roughly normally distributed.
• Positive merchant transactions are usually fixed salary payments - so the mode is taken.
• For personal transactions, the mode is imputed based on previous history of transactions between the 2 accounts numbers.
• There are 2 resulting edge cases which should be dropped.