Twenty-five sixth-grade students were asked to estimate how many hours a week they spend talking on the phone. This dot plot represents their reported number of hours of phone usage per week.

1. What percentage of the students reported not talking on the phone?

2. What percentage of the group reported talking on the phone for 3 hours?

3. How many hours would you say that these 25 students typically spend talking on the phone?
4. 1. How would you describe the spread of the data? Would you consider these students’ amounts of time on the phone to be alike or different? Explain your reasoning.
   2. Here is the dot plot from an earlier activity. It shows the number of hours per week the same group of 25 sixth-grade students reported spending on homework.

      

      Overall, are these students more alike in the amount of time they spend talking on the phone or in the amount of time they spend on homework? Explain your reasoning.

1. A keyboarding teacher wonders: “Do typing speeds of students improve after taking a keyboarding course?” Explain why her question is a statistical question.
2. The teacher records the number of words that her students can type per minute at the beginning of a course and again at the end. The two dot plots show the two data sets.

   

   A dot plot, beginning of course, 8 to 36 by 1's. Number of words per minute.  Beginning at 8, number of dots above each increment is 1, 1, 1, 0, 1, 0, 2, 1, 2, 0, 1, 2, 3, 1, 2, 1, 0, 1, 2, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0. 

   

   A dot plot, end of course, 8 to 36 by 1's. Number of words per minute. Beginning at 8, number of dots above each increment is 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 2, 2, 2, 1, 2, 3, 1, 2, 2, 1, 2, 1, 1, 0, 0.

   Based on the dot plots, do you agree with each of the following statements about this group of students? Be prepared to explain your reasoning.

   1. Overall, the students’ typing speed does not improve. They type at the same speed at the end of the course as they did at the beginning.
   2. 20 words per minute is a good estimate for how fast, in general, the students typed at the beginning of the course because it is near the center of the distribution.
   3. 20 words per minute is a good description of the center of the data set at the end of the course.
   4. There is more variability in the typing speeds at the beginning of the course than at the end, so the students’ typing speeds are more alike at the end.

3. Overall, how fast would you say that the students type after completing the course? What would you consider the center of the end-of-course data?