1. Cobra Electronics sells 42 brands of USB battery packs. These battery packs are power banks used by consumers to charge cell phones or supply power to portable electronic devices in the absence of a wall charger. The prices (to the nearest dollar) of these power packs are provided below, and you are asked to organize them into a grouped frequency distribution.

64 24 34 53 69 59 42

24 43 45 34 79 51 50

69 39 33 78 47 36 69

42 50 37 45 67 47 43

65 26 56 64 50 55 69

52 48 24 51 70 46 37

1. How many classes will you use? Show how you determined this. (1 mark)
2. (please show formula and working out for the answer)