[填空题]
A market research survey asked 200 teenage 6eb-kjp-g y3xdnxc 8.rs for the number of 9 s8w6r 9gp(2afkzic nminutes they spend on their phones on a daily basis. The results were recorded in n ia w9c86pk s9gz2f(rthe following 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.
