9514 1404 393
Answer:
- 4
- -2
- 4
- 2
- -2±√2
Step-by-step explanation:
In order to fill the first blank, we need to look at the second line to see what the coefficient of x is.
1. x² +<u> </u><u>4 </u>x +2 = 0
The constant is subtracted from both sides to get the second line.
2. x² +4x = <u> -2 </u>
The value that is added on the third line is the square of half the x-coefficient: (4/2)² = 4
3. x² +4x +<u> 4 </u> = -2 +4
On the fourth line, the left side is written as a square, and the right side is simplified. The square root is taken of both sides.
4. √(x +2)² = ±√<u> 2 </u>
Finally, 2 is subtracted from both sides to find the values of x.
5. x = <u> -2 ±√2 </u>
Answer:
Step-by-step explanation:
Hello!
For me, the first step to any statistics exercise is to determine what is the variable of interest and it's distribution.
In this example the variable is:
X: height of a college student. (cm)
There is no information about the variable distribution. To estimate the population mean you need a variable with at least a normal distribution since the mean is a parameter of it.
The option you have is to apply the Central Limit Theorem.
The central limit theorem states that if you have a population with probability function f(X;μ,δ²) from which a random sample of size n is selected. Then the distribution of the sample mean tends to the normal distribution with mean μ and variance δ²/n when the sample size tends to infinity.
As a rule, a sample of size greater than or equal to 30 is considered sufficient to apply the theorem and use the approximation.
The sample size in this exercise is n=50 so we can apply the theorem and approximate the distribution of the sample mean to normal:
X[bar]~~N(μ;σ2/n)
Thanks to this approximation you can use an approximation of the standard normal to calculate the confidence interval:
98% CI
1 - α: 0.98
⇒α: 0.02
α/2: 0.01

X[bar] ± 
174.5 ± 
[172.22; 176.78]
With a confidence level of 98%, you'd expect that the true average height of college students will be contained in the interval [172.22; 176.78].
I hope it helps!
Y = kx
Plug in what we know:
5 = k(8)
5 = 8k
Divide 8 to both sides:
k = 0.625
Plug this back into the equation along with y = 15:
y = kx
15 = 0.625x
Divide 0.625 to both sides:
x = 24
The propability is the least chance because it is the lowest time frame that it is on for
Answer B.
∑fx=1637,∑fx
2
=127663,∑f=21
x
ˉ
=Mean=
∑t
∑fx
=77.95
σ
2
=
∑f
∑fx
2
−(
x
ˉ
)
2
=
21
127663
−(77.95)
2
=2.987
σ=1.728