Answer:

--- Variance
Step-by-step explanation:
Given

Solving (a): Calculate the mean.
The given data is a grouped data. So, first we calculate the class midpoint (x)
For 51 - 58.

For 59 - 66

For 67 - 74

For 75 - 82

For 83 - 90

So, the table becomes:

The mean is then calculated as:



-- approximated
Solving (b): The sample variance:
This is calculated as:

So, we have:


-- approximated
Answer:
k>-2
Step-by-step explanation:
4k+15>-2k+3
4k-(-2k)+15>3
4k+2k+15>3
6k+15>3
6k>3-15
6k>-12
k>-12/6
k>-2
Answer:
1st one
Step-by-step explanation:
Because It is just like a right triangle.
Also, look at how the bird is formed, it looks like a right triangle.
Also, I know it's a right triangle because of the length given.
Hope this helped!
Answer:
32
Step-by-step explanation:
So the order of the points is: GHJK
GH = x+10 =JK
HJ=8
JK=2x-4
JK = x+10=2x-4
x+10=2x-4
10+4=2x-x
x=14
GH= 14+10 =24
GJ = GH +HJ = 24+ 8=32