Answer:
3.4
Step-by-step explanation:
Standard deviation of a population is defined as:
σ² = ∑(xᵢ − μ)² / n
The standard deviation of a sample is defined as:
s² = ∑(xᵢ − x)² / (n - 1)
It's not clear which one we have, so let's calculate both.
First, we must find the mean.
μ = (5+12+15+10+12+6+8+8) / 8
μ = 9.5
Now we find the squares of the differences:
(5-9.5)² + (12-9.5)² + (15-9.5)² + (10-9.5)² + (12-9.5)² + (6-9.5)² + (8-9.5)² + (8-9.5)²
= 80
Divide by n:
σ² = 80 / 8
σ² = 10
And take the square root:
σ = √10
σ ≈ 3.2
That's not one of the answers, so let's try the standard deviation of a sample instead of a population.
Instead of dividing by n, we'll divide by n-1:
s² = 80 / 7
And take the square root:
s = √(80/7)
s ≈ 3.4
So that must be it.
Answer:
Step-by-step explanation:
<h3>Solving linear equation with one variable:</h3>
1) -4 + 3x = 4x - 8
Add 4 to both sides
-4 + 3x + 4 = 4x - 8 + 4
3x = 4x - 4
Subtract 4x from both sides,
3x - 4x = -4x + 4x - 4
-x = -4
2) -5x - 8 = 2
Add 8 to both sides
-5x - 8 + 8 = 2 + 8
-5x = 10
Divide both sides by (-5)
3) 12r - 14 = 5(2-r)
12r - 14 = 5*2 - 5*r
12r - 14 = 10 - 5r
Add 14 to both sides
12r - 14 + 14 = 10 - 5r + 14
12r = 24 - 5r
Add 5r to both sides
12r + 5r = 24
17r = 24
Divide both sides by 17
r = 24/17
4) 3x - 8 = -(17 + 2x)
3x - 8 = -17 - 2x
Add 8 to both sides
3x - 8 + 8 = -17 - 2x + 8
3x = -9 - 2x
Add 2x to both sides
3x + 2x = -9
5x = -9
Divide both sides by 5
1/2 as a decimal is .5 ( it means .50) hoped it helped
(4a + 6b) x (2a - 2b)
the answer would be 8a2 + 4ab - 12b2
David will finish first, because if you divide Brad's miles by 2 to his miles in a 1/4 of an hour are 5.95 miles. This means David went 6.2 miles in the same time that Brad went 5.95. Therefore, David will finish first.
