Approximately 15% of peole are left-handed. If two people are selected at random, what is the probability of the following events?
P(At least one is right-handed)?
Is this correct?
1-P(none are RH)
so..1-P(LH and LH)
1-(.85)(.85)
=1-.7225
=.2775...is this correct?

Question

Approximately 15% of peole are left-handed. If two people are selected at random, what is the probability of the following events?
P(At least one is right-handed)?
Is this correct?
1-P(none are RH)
so..1-P(LH and LH)
1-(.85)(.85)
=1-.7225
=.2775...is this correct?

amistre64 · Answer

should we assume that people can either be left or right handed, but not both?

anonymous · Answer

well I guess it's possible to be both

anonymous · Answer

but I've never had a question ask me that...

amistre64 · Answer

since no stats are given as to ambidextrous peoples ... 

P(l) = .15,  P(r) = .85

at least one is P(l)

lr + ll

amistre64 · Answer

at least one is right handed that is ....

lr + rr

anonymous · Answer

Thank you! that makes sense.

amistre64 · Answer

the possible ways to choose 2 people are:

ll  .15*.15

lr   .15*.85
rl   .85*.15

rr  .85*.85

at least 1 r in it is:  lr + rl + rr

does that sound right?

amistre64 · Answer

1 - ll  :)  .9775

anonymous · Answer

yes it does. makes so much more sense. Thank you!

anonymous · Answer

wait so is the answer .85?

amistre64 · Answer

ll+lr+rl+rr = 1

lr+rl+rr = 1 - ll

since l = .15 ...

1 - .15^2 = .9775

anonymous · Answer

oh sorry I forgot the one part..thank you!