Is there any quick way to solve this question?
$begingroup$
Let $X$ be a random variable with the following cumulative distribution function
$$F(x) =
begin{cases}
{0}, & x<0 \[2ex]
x^2, & 0le x<dfrac{1}{2}\[2ex]
dfrac{3}{4}, &dfrac{1}{2}le x< 1 \[2ex]
1 & xge1
end{cases}$$
Find $P(dfrac{1}{4}<X<1)$
My input
Here I used $P(Xle x)= F(x) $ and $P(X< x)= F(x)^{*}$
At $dfrac{1}{2}$ our pdf is discontinuous and in the interval $0le x<dfrac{1}{2}$ $f(x)$ is continuous and in $dfrac{1}{2}le x< 1 $ it is discrete. So
$P(dfrac{1}{4}<X<dfrac{1}{2})+P( dfrac{1}{2}le x< 1 )=Fbigg(dfrac{1}{2}bigg)^{*}-Fbigg(dfrac{1}{4}bigg)+F(1)^{*}-Fbigg(dfrac{1}{2}bigg) + Pbigg(X=dfrac{1}{2}bigg)$
$= Fbigg(dfrac{1}{2}bigg)^{*}-Fbigg(dfrac{1}{4}bigg)+F(1)^{*}-Fbigg(dfrac{1}{2}bigg) + Fbigg(dfrac{1}{2}bigg)-Fbigg(dfrac{1}{2}bigg)^{*}$
$=F(1)^{*}-Fbigg(dfrac{1}{4}bigg)=dfrac{11}{16}$
So this question came in one mark. Is there any quick way to solve this ?
probability probability-distributions
$endgroup$
add a comment |
$begingroup$
Let $X$ be a random variable with the following cumulative distribution function
$$F(x) =
begin{cases}
{0}, & x<0 \[2ex]
x^2, & 0le x<dfrac{1}{2}\[2ex]
dfrac{3}{4}, &dfrac{1}{2}le x< 1 \[2ex]
1 & xge1
end{cases}$$
Find $P(dfrac{1}{4}<X<1)$
My input
Here I used $P(Xle x)= F(x) $ and $P(X< x)= F(x)^{*}$
At $dfrac{1}{2}$ our pdf is discontinuous and in the interval $0le x<dfrac{1}{2}$ $f(x)$ is continuous and in $dfrac{1}{2}le x< 1 $ it is discrete. So
$P(dfrac{1}{4}<X<dfrac{1}{2})+P( dfrac{1}{2}le x< 1 )=Fbigg(dfrac{1}{2}bigg)^{*}-Fbigg(dfrac{1}{4}bigg)+F(1)^{*}-Fbigg(dfrac{1}{2}bigg) + Pbigg(X=dfrac{1}{2}bigg)$
$= Fbigg(dfrac{1}{2}bigg)^{*}-Fbigg(dfrac{1}{4}bigg)+F(1)^{*}-Fbigg(dfrac{1}{2}bigg) + Fbigg(dfrac{1}{2}bigg)-Fbigg(dfrac{1}{2}bigg)^{*}$
$=F(1)^{*}-Fbigg(dfrac{1}{4}bigg)=dfrac{11}{16}$
So this question came in one mark. Is there any quick way to solve this ?
probability probability-distributions
$endgroup$
$begingroup$
$P(1/4<X<1)=F(1)^{ast}-F(1/4)$ by your definitions. The rest is redundant.
$endgroup$
– metamorphy
Dec 6 '18 at 12:41
$begingroup$
@metamorphy So it's always true if we have mixed distribution then valid too?
$endgroup$
– Daman deep
Dec 6 '18 at 12:45
add a comment |
$begingroup$
Let $X$ be a random variable with the following cumulative distribution function
$$F(x) =
begin{cases}
{0}, & x<0 \[2ex]
x^2, & 0le x<dfrac{1}{2}\[2ex]
dfrac{3}{4}, &dfrac{1}{2}le x< 1 \[2ex]
1 & xge1
end{cases}$$
Find $P(dfrac{1}{4}<X<1)$
My input
Here I used $P(Xle x)= F(x) $ and $P(X< x)= F(x)^{*}$
At $dfrac{1}{2}$ our pdf is discontinuous and in the interval $0le x<dfrac{1}{2}$ $f(x)$ is continuous and in $dfrac{1}{2}le x< 1 $ it is discrete. So
$P(dfrac{1}{4}<X<dfrac{1}{2})+P( dfrac{1}{2}le x< 1 )=Fbigg(dfrac{1}{2}bigg)^{*}-Fbigg(dfrac{1}{4}bigg)+F(1)^{*}-Fbigg(dfrac{1}{2}bigg) + Pbigg(X=dfrac{1}{2}bigg)$
$= Fbigg(dfrac{1}{2}bigg)^{*}-Fbigg(dfrac{1}{4}bigg)+F(1)^{*}-Fbigg(dfrac{1}{2}bigg) + Fbigg(dfrac{1}{2}bigg)-Fbigg(dfrac{1}{2}bigg)^{*}$
$=F(1)^{*}-Fbigg(dfrac{1}{4}bigg)=dfrac{11}{16}$
So this question came in one mark. Is there any quick way to solve this ?
probability probability-distributions
$endgroup$
Let $X$ be a random variable with the following cumulative distribution function
$$F(x) =
begin{cases}
{0}, & x<0 \[2ex]
x^2, & 0le x<dfrac{1}{2}\[2ex]
dfrac{3}{4}, &dfrac{1}{2}le x< 1 \[2ex]
1 & xge1
end{cases}$$
Find $P(dfrac{1}{4}<X<1)$
My input
Here I used $P(Xle x)= F(x) $ and $P(X< x)= F(x)^{*}$
At $dfrac{1}{2}$ our pdf is discontinuous and in the interval $0le x<dfrac{1}{2}$ $f(x)$ is continuous and in $dfrac{1}{2}le x< 1 $ it is discrete. So
$P(dfrac{1}{4}<X<dfrac{1}{2})+P( dfrac{1}{2}le x< 1 )=Fbigg(dfrac{1}{2}bigg)^{*}-Fbigg(dfrac{1}{4}bigg)+F(1)^{*}-Fbigg(dfrac{1}{2}bigg) + Pbigg(X=dfrac{1}{2}bigg)$
$= Fbigg(dfrac{1}{2}bigg)^{*}-Fbigg(dfrac{1}{4}bigg)+F(1)^{*}-Fbigg(dfrac{1}{2}bigg) + Fbigg(dfrac{1}{2}bigg)-Fbigg(dfrac{1}{2}bigg)^{*}$
$=F(1)^{*}-Fbigg(dfrac{1}{4}bigg)=dfrac{11}{16}$
So this question came in one mark. Is there any quick way to solve this ?
probability probability-distributions
probability probability-distributions
edited Dec 6 '18 at 12:48
Daman deep
asked Dec 6 '18 at 12:30
Daman deepDaman deep
749318
749318
$begingroup$
$P(1/4<X<1)=F(1)^{ast}-F(1/4)$ by your definitions. The rest is redundant.
$endgroup$
– metamorphy
Dec 6 '18 at 12:41
$begingroup$
@metamorphy So it's always true if we have mixed distribution then valid too?
$endgroup$
– Daman deep
Dec 6 '18 at 12:45
add a comment |
$begingroup$
$P(1/4<X<1)=F(1)^{ast}-F(1/4)$ by your definitions. The rest is redundant.
$endgroup$
– metamorphy
Dec 6 '18 at 12:41
$begingroup$
@metamorphy So it's always true if we have mixed distribution then valid too?
$endgroup$
– Daman deep
Dec 6 '18 at 12:45
$begingroup$
$P(1/4<X<1)=F(1)^{ast}-F(1/4)$ by your definitions. The rest is redundant.
$endgroup$
– metamorphy
Dec 6 '18 at 12:41
$begingroup$
$P(1/4<X<1)=F(1)^{ast}-F(1/4)$ by your definitions. The rest is redundant.
$endgroup$
– metamorphy
Dec 6 '18 at 12:41
$begingroup$
@metamorphy So it's always true if we have mixed distribution then valid too?
$endgroup$
– Daman deep
Dec 6 '18 at 12:45
$begingroup$
@metamorphy So it's always true if we have mixed distribution then valid too?
$endgroup$
– Daman deep
Dec 6 '18 at 12:45
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
$$Pleft(frac14<X<1right)=P(X<1)-Pleft(Xleqfrac14right)=lim_{xto1-}F(x)-Fleft(frac14right)=frac34-frac1{16}=frac{11}{16}$$
$endgroup$
$begingroup$
Always valid no conditions about continuity, discontinuity, discrete or continuous?
$endgroup$
– Daman deep
Dec 6 '18 at 12:47
$begingroup$
Indeed always valid.
$endgroup$
– drhab
Dec 6 '18 at 12:47
$begingroup$
What will be the probability at $P(X=dfrac{1}{2})$?
$endgroup$
– Daman deep
Dec 6 '18 at 12:49
$begingroup$
$P(X=frac12)=P(Xleqfrac12)-P(X<frac12)=F(frac12)-lim_{xtofrac12-}F(x)=frac34-frac14=frac12$
$endgroup$
– drhab
Dec 6 '18 at 12:51
$begingroup$
In your answer you wrote $Pbigg( X le dfrac{1}{4}bigg)$ but $Pbigg( X < dfrac{1}{4}bigg) $ is valid too write?
$endgroup$
– Daman deep
Dec 6 '18 at 12:53
|
show 1 more comment
Your Answer
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
$$Pleft(frac14<X<1right)=P(X<1)-Pleft(Xleqfrac14right)=lim_{xto1-}F(x)-Fleft(frac14right)=frac34-frac1{16}=frac{11}{16}$$
$endgroup$
$begingroup$
Always valid no conditions about continuity, discontinuity, discrete or continuous?
$endgroup$
– Daman deep
Dec 6 '18 at 12:47
$begingroup$
Indeed always valid.
$endgroup$
– drhab
Dec 6 '18 at 12:47
$begingroup$
What will be the probability at $P(X=dfrac{1}{2})$?
$endgroup$
– Daman deep
Dec 6 '18 at 12:49
$begingroup$
$P(X=frac12)=P(Xleqfrac12)-P(X<frac12)=F(frac12)-lim_{xtofrac12-}F(x)=frac34-frac14=frac12$
$endgroup$
– drhab
Dec 6 '18 at 12:51
$begingroup$
In your answer you wrote $Pbigg( X le dfrac{1}{4}bigg)$ but $Pbigg( X < dfrac{1}{4}bigg) $ is valid too write?
$endgroup$
– Daman deep
Dec 6 '18 at 12:53
|
show 1 more comment
$begingroup$
$$Pleft(frac14<X<1right)=P(X<1)-Pleft(Xleqfrac14right)=lim_{xto1-}F(x)-Fleft(frac14right)=frac34-frac1{16}=frac{11}{16}$$
$endgroup$
$begingroup$
Always valid no conditions about continuity, discontinuity, discrete or continuous?
$endgroup$
– Daman deep
Dec 6 '18 at 12:47
$begingroup$
Indeed always valid.
$endgroup$
– drhab
Dec 6 '18 at 12:47
$begingroup$
What will be the probability at $P(X=dfrac{1}{2})$?
$endgroup$
– Daman deep
Dec 6 '18 at 12:49
$begingroup$
$P(X=frac12)=P(Xleqfrac12)-P(X<frac12)=F(frac12)-lim_{xtofrac12-}F(x)=frac34-frac14=frac12$
$endgroup$
– drhab
Dec 6 '18 at 12:51
$begingroup$
In your answer you wrote $Pbigg( X le dfrac{1}{4}bigg)$ but $Pbigg( X < dfrac{1}{4}bigg) $ is valid too write?
$endgroup$
– Daman deep
Dec 6 '18 at 12:53
|
show 1 more comment
$begingroup$
$$Pleft(frac14<X<1right)=P(X<1)-Pleft(Xleqfrac14right)=lim_{xto1-}F(x)-Fleft(frac14right)=frac34-frac1{16}=frac{11}{16}$$
$endgroup$
$$Pleft(frac14<X<1right)=P(X<1)-Pleft(Xleqfrac14right)=lim_{xto1-}F(x)-Fleft(frac14right)=frac34-frac1{16}=frac{11}{16}$$
edited Dec 6 '18 at 12:48
answered Dec 6 '18 at 12:45
drhabdrhab
100k544130
100k544130
$begingroup$
Always valid no conditions about continuity, discontinuity, discrete or continuous?
$endgroup$
– Daman deep
Dec 6 '18 at 12:47
$begingroup$
Indeed always valid.
$endgroup$
– drhab
Dec 6 '18 at 12:47
$begingroup$
What will be the probability at $P(X=dfrac{1}{2})$?
$endgroup$
– Daman deep
Dec 6 '18 at 12:49
$begingroup$
$P(X=frac12)=P(Xleqfrac12)-P(X<frac12)=F(frac12)-lim_{xtofrac12-}F(x)=frac34-frac14=frac12$
$endgroup$
– drhab
Dec 6 '18 at 12:51
$begingroup$
In your answer you wrote $Pbigg( X le dfrac{1}{4}bigg)$ but $Pbigg( X < dfrac{1}{4}bigg) $ is valid too write?
$endgroup$
– Daman deep
Dec 6 '18 at 12:53
|
show 1 more comment
$begingroup$
Always valid no conditions about continuity, discontinuity, discrete or continuous?
$endgroup$
– Daman deep
Dec 6 '18 at 12:47
$begingroup$
Indeed always valid.
$endgroup$
– drhab
Dec 6 '18 at 12:47
$begingroup$
What will be the probability at $P(X=dfrac{1}{2})$?
$endgroup$
– Daman deep
Dec 6 '18 at 12:49
$begingroup$
$P(X=frac12)=P(Xleqfrac12)-P(X<frac12)=F(frac12)-lim_{xtofrac12-}F(x)=frac34-frac14=frac12$
$endgroup$
– drhab
Dec 6 '18 at 12:51
$begingroup$
In your answer you wrote $Pbigg( X le dfrac{1}{4}bigg)$ but $Pbigg( X < dfrac{1}{4}bigg) $ is valid too write?
$endgroup$
– Daman deep
Dec 6 '18 at 12:53
$begingroup$
Always valid no conditions about continuity, discontinuity, discrete or continuous?
$endgroup$
– Daman deep
Dec 6 '18 at 12:47
$begingroup$
Always valid no conditions about continuity, discontinuity, discrete or continuous?
$endgroup$
– Daman deep
Dec 6 '18 at 12:47
$begingroup$
Indeed always valid.
$endgroup$
– drhab
Dec 6 '18 at 12:47
$begingroup$
Indeed always valid.
$endgroup$
– drhab
Dec 6 '18 at 12:47
$begingroup$
What will be the probability at $P(X=dfrac{1}{2})$?
$endgroup$
– Daman deep
Dec 6 '18 at 12:49
$begingroup$
What will be the probability at $P(X=dfrac{1}{2})$?
$endgroup$
– Daman deep
Dec 6 '18 at 12:49
$begingroup$
$P(X=frac12)=P(Xleqfrac12)-P(X<frac12)=F(frac12)-lim_{xtofrac12-}F(x)=frac34-frac14=frac12$
$endgroup$
– drhab
Dec 6 '18 at 12:51
$begingroup$
$P(X=frac12)=P(Xleqfrac12)-P(X<frac12)=F(frac12)-lim_{xtofrac12-}F(x)=frac34-frac14=frac12$
$endgroup$
– drhab
Dec 6 '18 at 12:51
$begingroup$
In your answer you wrote $Pbigg( X le dfrac{1}{4}bigg)$ but $Pbigg( X < dfrac{1}{4}bigg) $ is valid too write?
$endgroup$
– Daman deep
Dec 6 '18 at 12:53
$begingroup$
In your answer you wrote $Pbigg( X le dfrac{1}{4}bigg)$ but $Pbigg( X < dfrac{1}{4}bigg) $ is valid too write?
$endgroup$
– Daman deep
Dec 6 '18 at 12:53
|
show 1 more comment
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$begingroup$
$P(1/4<X<1)=F(1)^{ast}-F(1/4)$ by your definitions. The rest is redundant.
$endgroup$
– metamorphy
Dec 6 '18 at 12:41
$begingroup$
@metamorphy So it's always true if we have mixed distribution then valid too?
$endgroup$
– Daman deep
Dec 6 '18 at 12:45