[填空题]
A market research survey asked 2zympfpylg740xtj 1y6z /.*j n 00 8 jdhzm/mi9m9q dp er 9;vm.:gteenagers for the number of minutes they spend on their phones on a daily basis. The results were recorded in the following box-and-whis9dd e m8g9;m9hip / :rm.zmvjqker 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.
