There are 21 televisions.
Class 1077-1136:
The frequency is how many of them cost in this range.
There is 1.
So frequency: 1
Relative frequency is 1/21 = 0.0476
Cumulative frequency is the previous cumulative plus the relative:
Previous cumulative: 0
Relative: 0.0476
Cumulative = 0 + 0.0476 = 0.0476
Class 1137-1196:
6 in this interval.
Frequency: 6
Relative frequency: 6/21 = 0.2857
Previous cumulative: 0.0476
Relative: 0.2857
Cumulative = 0.0476 + 0.2857 = 0.3333
Class 1197-1256:
7 in this interval.
Frequency: 7
Relative frequency: 7/21 = 0.3333
Previous cumulative: 0.3333
Relative: 0.3333
Cumulative: 0.3333 + 0.3333 = 0.6666
Class 1257-1316:
2 in this interval.
Frequency: 2
Relative frequency: 2/21 = 0.0952
Previous cumulative: 0.6666
Relative: 0.0952
Cumulative: 0.6666 + 0.0952 = 0.7618
Class 1317-1376:
2 in this interval.
Frequency: 2
Relative frequency: 2/21 = 0.0952
Previous cumulative: 0.7618
Relative: 0.0952
Cumulative: 0.7618 + 0.0952 = 0.857
Class 1377-1436:
3 in this interval.
Frequency: 3
Relative frequency: 0.143
Previous cumulative: 0.857
Relative: 0.143
Cumulative: 0.857+0.143 = 1