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)
Let the number of thirds be x.
(2/5) = x(1/3)
2/5 = x/3
x/3 = 2/5
x = 2/5 * 3
x = 6/5
x = 1.2
Two-fifths equals 1.2 thirds
1) function 2) not a function
the first one is a function because its y values are the same number (3), which means it is a horizontal line and horizontal lines are functions.
the second one is not a function because the coordinates cannot have different inputs but different outputs. each input must have only one output.
the coordinates for the second one are:
(2,5); (1,1); (1,2); (3,2)
and <u>a function cannot have two same x-coordinates</u>. it must pass the vertical line test which is a way to tell if something is a function or not. since the second graph does not pass the vertical line test, it is not a function
hope this helps :)
