For this question, all you have to do is subtract 6 from 10 to get 4. 4 + 6 is 10. z = 4.
Answer:
The process of digging a site includes
D or B
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
Answers:
B = 50
a = 10.9
c = 17.0
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Explanation:
This is a right triangle, so the acute angles are complementary, meaning they add to 90
B+40 = 90
B+40-40 = 90-40
B = 50
Also, because this is a right triangle, we can use trig ratios to compute the missing sides
tan(angle) = opposite/adjacent
tan(40) = a/13
a = 13*tan(40)
a = 10.908
a = 10.9
cos(angle) = adjacent/hypotenuse
cos(40) = 13/c
c*cos(40) = 13
c = 13/cos(40)
c = 17.0
note: make sure your calculator is in degree mode