7. (6 pts.) There are approximately 275 active telephone area codes covering Canada, the United States, and some Caribbean areas. You want to choose an SRS of 20 of these area codes for a study of available telephone numbers. (a) Describe how you will use labels in order to select the sample. Identify the unused labels also clearly. (b) Use the following random numbers to illustrate the selection of the rst 5 area codes in the SRS. 12975 13298 13048 45144 72321 81940 00360 02428 96767 35964 23822 96012