Survey

#1
For homework in statistics I had to make my own survey. For the topic I chose: "On average how many hours do students spend on doing homework daily?" I decided to use straightified method of sampling, so I wanted to ask 10 students from 10th grade and 10 students from 11th grade. I asked my friend from Russia to help me to make a survey in her school and she gave me the results:
11th grade: 2 answers 0-1 hours, 6 answers 2-3 hours and 2 answers 3-5 hours
10th grade: 9 answers 2-3 hours, 1 - 0 hours.

I am thinking to make a dot plot, a pie chart and a histogram.
Can you suggest me some other graphs that I can make to make it more presentable? And what to do with 10th graders, if there were only 2 types of answers? And, I am sorry, from your opinion is this information biased?

Thank you very much for all your help!:)
 
#2
Alex,

A boxplot would also be helpful. It shows the median and variability of the three groups.

I don't know how the students were selected. If you have a sampling scheme, which could be random or systematic, then it's not biased.