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:
1 and 2 are not polyhedrons, as a circle has infinite sides
1. cone, 1 vertex
2. sphere, nothing
3. pentagonal prism?
wait but can't every face be a base???
anyway 7 faces, 10 vertices
4. triangular prism
5 faces, 6 vertices
Step-by-step explanation:
Answer:
5 1/4 cups
Step-by-step explanation:
7x3/4= 5 1/4
Answer:
a,d,c
Step-by-step explanation:
15% of 4,000,751,546,368= 15/100x4,000,751,546,368 = 600,112,731,955.6