Answer:
a. E(x) = 3.730
b. c = 3.8475
c. 0.4308
Step-by-step explanation:
a.
Given
0 x < 3
F(x) = (x-3)/1.13, 3 < x < 4.13
1 x > 4.13
Calculating E(x)
First, we'll calculate the pdf, f(x).
f(x) is the derivative of F(x)
So, if F(x) = (x-3)/1.13
f(x) = F'(x) = 1/1.13, 3 < x < 4.13
E(x) is the integral of xf(x)
xf(x) = x * 1/1.3 = x/1.3
Integrating x/1.3
E(x) = x²/(2*1.13)
E(x) = x²/2.26 , 3 < x < 4.13
E(x) = (4.13²-3²)/2.16
E(x) = 3.730046296296296
E(x) = 3.730 (approximated)
b.
What is the value c such that P(X < c) = 0.75
First, we'll solve F(c)
F(c) = P(x<c)
F(c) = (c-3)/1.13= 0.75
c - 3 = 1.13 * 0.75
c - 3 = 0.8475
c = 3 + 0.8475
c = 3.8475
c.
What is the probability that X falls within 0.28 minutes of its mean?
Here we'll solve for
P(3.73 - 0.28 < X < 3.73 + 0.28)
= F(3.73 + 0.28) - F(3.73 + 0.28)
= 2*0.28/1.3 = 0.430769
= 0.4308 -- Approximated
Answer:
2
Step-by-step explanation:
Answer:
20+7x
Step-by-step explanation:
you'd multiply 2 by 5 and 2 by 3x which will give you 10+ 6x; Then add the others : 2(5+3x)+(x+10) would be 10+6x+x+10 so its 20+7x. .
Quadratic formula is x = -b+ or- sq rt b^2-4ac / 2a
a=2 b=5 c=-3
-5 +or- sqrt 5^2-4(2)(-3) / 2(2)
-5 +or- sqrt 49/ 4
-5 + 7 /4 = 2/4 = 1/2
-5 - 7 /4 = -12/4 = -3
Factoring a*c is 2*-3 =-6
Factors of -6 that add to 5 are 6 and -1
Split 5x into +6x-1x
2x^2+6x-1x-3 and group
2x(x+3)-1(x+3)
(x+3)(2x-1)=0
x+3=0 gives x=-3
2x-1=0 gives x=1/2
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Step-by-step explanation: