Answer:
Step-by-step explanation:
The standard deviation is the square root of the variance, and the variance is found by using the mean. So we will do that first. I will use the population variance as opposed to the sample variance since our set of numbers is small.
The mean: 8 + 12 + 15 + 17 + 18 = 70 and divide that by 5 to get
and use this to find the variance in the formula:
it is a bit difficult to enter that formula in correctly, but here's how it works mathematically:

Squaring this ensures us that we don't end up with zero, which would be useless.
so
which means that the standard deviation is
s = 3.633
(If you do it with n-1 = 4 in the denominator of the variance, you get a standard deviation of 4.062)
<span>tan θ is defined as the opposite/adjacent side to the angle in a triangle
in this case you have a triangle which forms from (0,0) to (5,0) and (5,15), with </span><span>θ at (0,0)
-> your x coordinate is the adjacent side, and y the opposite
</span>
<span>tan θ=opposite/adjacent=y/x=15/5=3</span>