Simplify 1/4 y + 1 1/2 + 2 -1 3/4y -12
1 answer:
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Answer:
a) c=3/4
b) for -1<x<1
F(x) = (3/4) ( x + (2-x^3)/3 )
c)
E(x)=0
Var(x) = 1/5
Step-by-step explanation:
Hi!
a)
In order to f(x) be a probability density function it must be normalized, which means that its integral must be equal to 1:
Since f(x) is zero for x>1 and x<-1
Therefore:
c=3/4
b)
The cumulative distribution fucntion F(x) can be obtained integrating f(x) from -∞ to x:
Since f(x) = 0 for x<-1
F(x) = 0 for x<-1
for -1<x<1:
for x>1
F(x)=1
c)
The mean E(x) can be found integrating xf(x)
We can easily infer that the mean must be zero, since f(x) is an even function and thus xf(x) is an odd function integrated in a simetric interval:
E(x) = 0
The variance of x, Var(x), can be evaluated integrating (x-E(x))^2f(x), since E(x)=0:
Since c=3/4
Var(x) = 1/5
You can try the points and see which satisfy the relation. I find it easier to consult a graph of the solution set and the offered points.
The appropriate choice is ...
... C: (1, 0) . . . . . . . on the boundary of the solution set.
Step-by-step explanation:
Answer is in the pic above
