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.
The slope of the line is -4
First, we need to transform the equation into its standard form (x - h)²=4p(y - k).
Using completing the square method:
y = -14x² - 2x - 2
y = -14(x² + 2x/14) - 2
y = -14(x² + 2x/14 + (2/28)²) -2 + (2/28)²
y = -14(x + 1/14)² - 391/196
-1/14(y + 391/196) = (x + 1/14)²
This is a vertical parabola and its focus <span>(h, k + p) is (-1/14, -391/196 + 1/56) = (-1/14, -775/392).
Or (-0.071,-1.977).</span>
Answer:
a = -3
Step-by-step explanation:
Solve for a:
2 (a + 5) - 1 = 3
Hint: | Distribute 2 over a + 5.
2 (a + 5) = 2 a + 10:
(2 a + 10) - 1 = 3
Hint: | Group like terms in 2 a - 1 + 10.
Grouping like terms, 2 a - 1 + 10 = 2 a + (10 - 1):
(2 a + (10 - 1)) = 3
Hint: | Evaluate 10 - 1.
10 - 1 = 9:
2 a + 9 = 3
Hint: | Isolate terms with a to the left hand side.
Subtract 9 from both sides:
2 a + (9 - 9) = 3 - 9
Hint: | Look for the difference of two identical terms.
9 - 9 = 0:
2 a = 3 - 9
Hint: | Evaluate 3 - 9.
3 - 9 = -6:
2 a = -6
Hint: | Divide both sides by a constant to simplify the equation.
Divide both sides of 2 a = -6 by 2:
(2 a)/2 = (-6)/2
Hint: | Any nonzero number divided by itself is one.
2/2 = 1:
a = (-6)/2
Hint: | Reduce (-6)/2 to lowest terms. Start by finding the GCD of -6 and 2.
The gcd of -6 and 2 is 2, so (-6)/2 = (2 (-3))/(2×1) = 2/2×-3 = -3:
Answer: a = -3
I = PRT
14,300 = (700)(0.0725)(t)
14,300 = 50.75(t)
14300/50.75 = t
281.77 = t or t = 281.77
hope this helps :)
