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:
-6r+6
Step-by-step explanation:
Given data
We are given the expression
8-(6r+2)
let us expand it by opening the bracket
=8-6r-2
collect like terms
=8-2-6r
=6-6r
rearrange
=-6r+6
Hence option A is correct
Answer:
2/5
Step-by-step explanation:
C is at the second tick of 6 segements, so C = 2/6 = 1/3.
If we convert all fractions to /60, you can easily see the answer:
1/3 = 20/60
2/5 = 24/60
1/4 = 15/60
1/5 = 12/60
So we're looking for an answer larger than 20/60, which is only 24/60, a.k.a. 2/5.
Answer:
the second option : 5 1/3
Step-by-step explanation:
the height (h) in such a right-angled triangle is based on the 2 segments of the baseline : 3 and a
h = 4
the formula is h = sqrt(a×b)
with a and b being the baseline segments.
so,
4 = sqrt(3×a)
16 = 3×a
a = 16/3 = 5 1/3