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.
It'll be at 11:11 when the hands form a obtuse angle.
Answer:
the number --4
Step-by-step explanation:
-7--4=-3
-3--4=1
1--4=5
5--4=9
Answer:
B. feet/second
Step-by-step explanation:
If they have 24 hours in a day, and use 1/6 of those 24 hours on news, they use 24*(1/6) or 4 hours on news. Assuming that they use the leftover time for just music and entertainment, we have 20h - 4h, so thats 20h. You were right. Not sure on their reasoning either.
