To get the variance, start with finding the mean of your data points:
(23 + 19 + 22 + 30 + 28) / 5 = 24.4
Now take each data point and subtract the mean from it, then square that value:
23 - 24.4 = -1.4 * -1.4 = 1.96
19 - 24.4 = -5.4 * -5.4 = 29.16
22 - 24.4 = -2.4 * -2.4 = 5.76
30 - 24.4 = 5.6 * 5.6 = 31.36
28 - 24.4 = 3.6 * 3.6 = 12.96
Now get the average of those new numbers. That is your variance:
(1.96 + 29.16 + 5.76 + 31.36 + 12.96) / 5 = 16.24
The standard deviation will be the square root of the variance:
√(16.24) = 4.0299 (rounded to 4DP)
Answer:
its 1
Step-by-step explanation:
Answer:
1) 
2) 
Step-by-step explanation:
1)

Subtract 15 from both sides

Divide both sides by 2




this shows that 10 is the right answer
2)

Add 3 to both sides

Divide both sides by 7




this shows that 3 is the right answer
Hope this helps
You plug in the values for x in each respective equation.
a) f(3) = 3 + 1 which equals: 4.
so, f(3) = 4
b) g(3) = (3)^2 - 3 which equals 9 - 3, which equals 6.
so, g(3) = 6.
hope this helps! (:
Pretty sure the answer is 77