Should Children Be Paid for Good Grades?

The purpose of this research was to determine if parents should pay children to motivate them to get good grades. Through written surveys, I found that there are no difference between parents and adult children concerning the importance of good grades and the influence on teachers and parents on good grades.
There is a difference between parents and adult children concerning the self-motivation for good grades, the influence of peers on good grades, the importance of being rewarded for good grades, and parents paying children for good grades.

Parents were limited to those that have had at least one child graduate from high school.
Pay is a monetary reward announced to the child and offered as an incentive for making good grades.
The children for this case will include high school ages, 14-18.
Good grades are considered to be "As" and "Bs"

Individual graphic data:
Parent One: Female, age 36-48. She has one child that attended private school and graduated from high school and used money for reward for good grades in high school.

Parent Two: Female, age 36-48. She has two children who attended public school, but only one graduated from high school. She doesn't believe in using money as a reward.

Parent Three: Male, age 49-61. He has four children who attended public school and graduated from high school. He doesn't believe in using money as a reward for god grades.

Adult Child One: Female, younger than 23. 8 children in the family, including her, have graduated high school. One child attended private school for a short period and all eight attended public school. Her parents used money as a reward for good grades.

Adult Child Two: Female, younger than 23. 3 children in the family, including her, have attended public school. She is the only one to graduate from high school so far. Her parents never rewarded her with money for good grades.

Adult Child Three: Female, younger than 23. 2 children in the family, including her, have attended public school and graduated from high school. Her parents never rewarded good grades with money.
The sample is a non-probability purposive sample. I am selecting participants who graduated from high school, but are not in high school now. And parents who have at least one child who graduated from high school, but is not in high school now.

Hypotheses:
Accept that there is no difference between parents and children regarding the importance of good grades.

100% of parents and children agree that good grades are important.
Reject that there is no difference between parents and children regarding self-motivation for good grades.

100% of parents and 33% of children believe that motivation is self-imposed, not encouraged.

66% of children believe that motivation is not self-imposed, but encouraged.
Accept that there is no difference between parents and children regarding the influence of teachers on good grades.

100% of parents and children believe that teachers have influence on grades.
Accept that there is no difference between parents and children regarding the influence of parents on good grades.

100% of parents and children believe that parents have influence on grades.
Reject that there is no difference between parents and children regarding the influence of peers on good grades.

66% of parents and children believe that peers have influence on grades.

33% of parents and children believe that peers do not have influence on grades.
Reject that there is no difference between parents and children regarding the importance of being rewarded for good grades.

100% of parents and 66% of children believe that rewarding for good grades is important.

33% of children believe that rewarding for good grades is not important.

Reject there is no difference between parents and children regarding parents paying children to get good grades.

33% of parents believe that children should be paid to get good grades.
66% of parents and 100% of children believe that children should not be paid to get good grades.