Answer:
Y=4Z
Step-by-step explanation:
Answer:
(a) P(X = 18) = 0.25
(b) P(X > 18) = 0.53
(c) P(X ≤ 18) = 0.47
(d) Mean = 19.76
(e) Variance = 22.2824
(f) Standard deviation = 4.7204
Step-by-step explanation:
We are given that discrete random variable X has the following probability distribution:
X P (x) X * P(x) * P(x)
13 0.22 2.86 169 37.18
18 0.25 4.5 324 81
20 0.20 4 400 80
24 0.17 4.08 576 97.92
27 0.16 4.32 729 116.64
(a) P ( X = 18) = P(x) corresponding to X = 18 i.e. 0.25
Therefore, P(X = 18) = 0.25
(b) P(X > 18) = 1 - P(X = 18) - P(X = 13) = 1 - 0.25 - 0.22 = 0.53
(c) P(X <= 18) = P(X = 13) + P(X = 18) = 0.22 + 0.25 = 0.47
(d) Mean of X, = ∑X * P(x) ÷ ∑P(x) = (2.86 + 4.5 + 4 + 4.08 + 4.32) ÷ 1
= 19.76
(e) Variance of X, = ∑ * P(x) -
= 412.74 - = 22.2824
(f) Standard deviation of X, = = = 4.7204 .
The probabilities for the given X values are calculated by summing the relevant given probabilities. The mean of X is computed as a weighted average, and the variance and standard deviation are calculated using formula involving the mean and the individual probabilities.
The probability P(18) is given as 0.25 according to the distribution. The probability P(X > 18) is the sum of the probabilities for all x > 18, so we add the probabilities for x=20, x=24, and x=27, giving us 0.20 + 0.17 + 0.16 = 0.53. The probability P(X ≤ 18) includes x=18 and any values less than 18. As 18 is the lowest value given, P(X ≤ 18) is just P(18), or 0.25.
The mean μ of X is the expected value of X, computed as Σ(xP(x)). That gives us (13*0.22) + (18*0.25) + (20*0.20) + (24*0.17) + (27*0.16) = 2.86 + 4.5 + 4 + 4.08 + 4.32 = 19.76.
The variance σ 2 of X is computed as Σ [ (x - μ)^2 * P(x) ]. That gives us [(13-19.76)^2 * 0.22] + [(18-19.76)^2 * 0.25] + [(20-19.76)^2 * 0.20] + [(24-19.76)^2 * 0.17] + [(27-19.76)^2 * 0.16] = 21.61. The standard deviation σ of X is the sqrt(σ^2) = sqrt(21.61) = 4.65.
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Answer: B
Step-by-step explanation:
To find the inverse function, you switch x with y and y with x. Then, you solve for y.
[switch x with y, and y with x]
[add both sides by 4]
[square root both sides]
[add both sides by 1]
Now that we know the inverse function, we can actually tell that the answer is B. We know this because of the restriction that f(x) is x≤1. This makes it positive, and B the answer.
Answer:
Step-by-step explanation:
Hello!
Research.
n=9 frail elderly were interview and compared to a fictitious person who was worse off then the interviewee, a life-satisfaction score was determined for each person.
18, 23, 24, 22, 19, 27, 23, 26, 25
Assuming that the population average score is μ= 20, the researchers think that the elderly in the sample are more or less satisfied than others in the general population.
a. You have the information of one sample, assuming this sample has a normal distribution and each elderly interviewed is independent, then the t-test of choice is a one-sample t-test.
b. and c. If you say that the elderly are "more or less" satisfied than the others, this means that they are either as satisfied as to the general population or not satisfied as to the general population. Symbolically:
H₀: μ = 20
H₁: μ ≠ 20
This is a two-tailed test, meaning, you will have two critical regions.
d.
α: 0.05
Left critical value:
Right critical value:
e.
X[bar]= 23
S= 3
f.
Considering that the calculated t-value is greater than the right critical value, the decision is to reject the null hypothesis, so using a significance level of 5% you can conclude that the average life-satisfaction score of the elderly is different than 20.
I hope it helps!
Answer:
B. -2t^2+3t+4
Step-by-step explanation:
The standard form as
ax^2 + bx + c
Option B meets that requirement, even though it has a '-' in front
All the given polynomials, A. t^4-1, B. -2t^2+3t+4 and C. 4t-7 are in standard form since their terms are written in descending order of their degrees.
In mathematical terms, a polynomial is in standard form if its terms are written in descending order of their degree, i.e. the power of the variable. This means the term with the highest power should be listed first, followed by the term with the next highest power, and so on. Let's look at the options:
So, in conclusion, the polynomials in standard form from the provided options are A. t^4-1, B. -2t^2+3t+4 and C. 4t-7.
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Answer:
Choice B: Only (-2, 9)
Step-by-step explanation:
Of the two choices, only the point (-2, 9) satisfies the equation:
... y = -2x +5
... 9 = -2(-2) +5 = 4 +5 = 9
Answer:
The correct answer is B. Only (-2,9) is a solution of the equation.
Step-by-step explanation:
To figure out if an ordered pair is a solution to an equation, you could perform a test.
Identify the x-value in the ordered pair and plug it into the equation. When you simplify, if the y-value you get is the same as the y-value in the ordered pair, then that ordered pair is indeed a solution to the equation.
We have the equation
and two different ordered pairs (2, -9) and (-2, 9).
We use the x-value in the first ordered pair, x = 2, and we plug it into the equation.
If we compare with the ordered pair (2, -9), y must be equal to -9, but when we plugged x = 2 into the equation, we obtained that y = 1, so this is not a solution.
Using the x-value of the second ordered pair, x = -2, we get
Because we obtained y = 9, when we plugged x = -2, the ordered pair (-2, 9) is a solution of the equation.
The correct answer is B. Only (-2,9) is a solution of the equation.