81% of the money spent at full-service restaurants in America takes place by debit, credit, or pre-paid cards. One restaurant kept data for the week, and found that 421 of it's 973 customers used either debit, credit, or pre-paid cards to pay for their meal that week. Choose all possible reasons for the discrepancy in the results. Choices:
1. The theoretocal probability is not calculated correctly

2. the experiment is flawed

3. enough trials have not been performed to give the desired result .

4. there is no discrepancy in the result
choose all answers that apply. ​