A confounding variable is an extraneous variable that is related to your independent variable and might affect your dependent variable. In an ideal study, there will be no confounding variables.
For example, student accounts have a limit of $100 limit per day, while non-business accounts usually are limited to $500 withdrawals a day. For business accounts, the bank offers $1000 withdrawals in one day. Chase also offers customers a withdrawal limit of $1000 every 24 hours.
Many banks set daily withdrawal limits, and you won't be able to withdraw amounts in excess of these limits. In some cases, however, you might be able to get your bank to lift the limit. Each bank can establish its own daily withdrawal limit, but limits usually range from $500 to $1,000 or so.