The given pie chart illustrates how much time students spent for preparation, while the bar chart represents the average mark of students based on the amount of time they studied.
Overall, it is evident that overwhelming majority of students spent from 51 to 75 hours. The bar chart demonstrates a clear correlation, indicating that as the time spent on studying increased, the average score rose consistently, except for students who studied 101-125 hours.
According to the pie chart, the vast majority (38%) studied for 51-75 hours. This was followed by the students who prepared between 76-100 hours, illustrating exactly 30%. In addition, 18% of students studied 26-50 hours, and 9% spent between 101 and 125 hours, whereas only the tiny minority (5%) spent 0-25 hours.
Regarding bar chart, the average mark of students who spent 0-25 hours was 40%. This figure increased as the amount of time rose, displaying slightly over 60% for the students who prepared for 26-50 hours, and approximately 75% for 51-75 hours of studying. The highest average score, around 90%, was observed for students who spent between 76 and 100 hours. By contrast, the average of those who spent more than 101 hours on preparation showed just over 80%.