 #1
 77
 1
Homework Statement:
 probability three event
Relevant Equations:

i could find ##P(T \cup F) = P(T)+P(F)P(T \cap F)=55\% +53\%20\%=88% ## is this right?
##P(T) =35## but i dont know ##P(T \cap I)##
A questionnaire survey on the use of SNS was conducted for students at A University. As a result,
we got the following:
##55\%## using Twitter ,
##53\%## using Facebook ,
##20\%## using Twitter and facebook both,
##19\%## use both Facebook and
Instagram.
##76\%## use at least Twitter
and / or Instagram
##72\%## use at least one of Facebook
and Instagram
##49\%## use only one of twitter ,facebook, or instagram
At this time, find the next
ratio respectively.
##1##. Percentage of using both
Twitter and Instagram
##2##. Percentage of using all
of Twitter, Facebook and Instagram
##3##. Percentage of not using
either Twitter, Facebook or Instagram
I was confused, for ##P(T\cap F)=20\%## does this also include ##P(T\cap F \cap I )## ?
for ##P(F) ## pnly ##P(F\cap T)##, is it correct only facebook is ##14\%##?
##P(F)=53\%  P(F\cap T)  P(F\cap I)=53\%19\%20\% =14\%##?
i could find ##P(T \cup F) = P(T)+P(F)P(T \cap F)=55\% +53\%20\%=88% ##
is this right?
##P(T) =35##
but i dont know
##P(T \cap I)##
P(F)=14
i manage to find :
##P(T \cap I) = 17## and ##P(I)=38##
but when i count
##P(T \cup F \cup I) = P(T)+P(F)+P(I)P(T \cap F)  P(T \cap I)  Ｐ(I \cap F) + P(T \cap F \cap I) = ##
##49=55+53+38201917 +P(T \cap F \cap I) ##
##P(T \cap F \cap I)=41##
we got the following:
##55\%## using Twitter ,
##53\%## using Facebook ,
##20\%## using Twitter and facebook both,
##19\%## use both Facebook and
Instagram.
##76\%## use at least Twitter
and / or Instagram
##72\%## use at least one of Facebook
and Instagram
##49\%## use only one of twitter ,facebook, or instagram
At this time, find the next
ratio respectively.
##1##. Percentage of using both
Twitter and Instagram
##2##. Percentage of using all
of Twitter, Facebook and Instagram
##3##. Percentage of not using
either Twitter, Facebook or Instagram
I was confused, for ##P(T\cap F)=20\%## does this also include ##P(T\cap F \cap I )## ?
for ##P(F) ## pnly ##P(F\cap T)##, is it correct only facebook is ##14\%##?
##P(F)=53\%  P(F\cap T)  P(F\cap I)=53\%19\%20\% =14\%##?
i could find ##P(T \cup F) = P(T)+P(F)P(T \cap F)=55\% +53\%20\%=88% ##
is this right?
##P(T) =35##
but i dont know
##P(T \cap I)##
P(F)=14
i manage to find :
##P(T \cap I) = 17## and ##P(I)=38##
but when i count
##P(T \cup F \cup I) = P(T)+P(F)+P(I)P(T \cap F)  P(T \cap I)  Ｐ(I \cap F) + P(T \cap F \cap I) = ##
##49=55+53+38201917 +P(T \cap F \cap I) ##
##P(T \cap F \cap I)=41##