What is the full question ?
the answer is in the picture above
Answer:
Step-by-step explanation:
Combine 
Combine the bottom, too.
Apply the fraction rule
Cancel
Therefore, 
Answer:
Standard Deviation = 5.928
Step-by-step explanation:
a) Data:
Days Hours spent (Mean - Hour)²
1 5 61.356
2 7 34.024
3 11 3.360
4 14 1.362
5 18 26.698
6 22 84.034
6 days 77 hours, 210.834
mean
77/6 = 12.833 and 210.83/6 = 35.139
Therefore, the square root of 35.139 = 5.928
b) The standard deviation of 5.928 shows how the hours students spend outside of class on class work varies from the mean of the total hours they spend outside of class on class work.
Answer:
72
Step-by-step explanation:
18 + 18 + 6 + 6 + 12 + 12
