[填空题]
A market research su4q+ow27 qw3;r p2 dcjzzibhw9rv(ppb ce0l a:d+ey asked 200 teenagers for the number of minutes they spend on their phones on a daily basis. The results were recorded in the focep (pl a+d:0bllowing box-and-whisker diagram.
1. Write down the median.
The following incomplete table shows the distribution of the responses from these 200 teenagers. minutes
2. Complete the table.
3. (1) Write down the mid-interval value for the $80 (2) Using the table, calculate an estimate for the mean number of minutes spent on phones daily by these 200 teenagers. ≈ minutes
The 200 teenages were chosen for the survey by randomly selecting student ID numbers in a school, using a random number generator.
4. Identify the sampling method used.
