Question

More statistics.
Binomial Probability
\[P(r)=\frac{n!}{r!(n-r)!}p^rq^{n-r}=C_{n,r}p^rq^{n-r}\]
The problem states 10% of adults deliberately do a one time fling (purchase clothing, wear 'em to an event, and return 'em).

In a group of 7 adults what is the probability that anyone has done a one time fling?

I figured that:
n=7
r=0

I plugged those into the equation:
\[P(0)=\frac{7!}{0!(7-0)!}p^0q^{7-0}=C_{7,0}p^0q^{7-0}\]

What about p and q?
The probability of success (p) is 0.1 (1% of people do one time flings)?
and q would be 0.9? Would that be right?

Answer 1

@hartnn

Answer 2

@mathslover ?

Answer 3

are u sure about n=7, r= 0 ?

Answer 4

out of 7, any'one' has done a one....
so do u feel r should be 1 ?

Answer 5

the probability of success = probability of flinging = p = 10% = 0.1 \(\checkmark\)
the probability of failure = probability of not flinging = q = 90% = 0.9 \(\checkmark\)

Answer 6

just clear your confusion about, n and r

Answer 7

oh sorry I was gone for while. Let's see here. Give me a second to read everything. Sorry :S

Answer 8

Ok so about n and r.
#number of trials
How do I relate that to this problem? I guessed that n=7 because it looked nice, but I don't have a good explanation for why I picked it

Answer 9

I meant n=# of trials

Answer 10

number of trials or events or no. of creatures/people on which experiment is performed = n =7 here, \(\checkmark\)

Answer 11

r is the number of people 'chosen'
here probability that anyONE has done fling implies, r=1
make sense?
or more explanation?

Answer 12

so when we say r=0...

Answer 13

almost never.....when we don't perform experiment.....maybe there are some special case for this

Answer 14

make sure u understand why n=7, r=1 here

Answer 15

When no one has done a fling wouldn't that be r=0?

Answer 16

umm, yes i think so....(0.9)^7 seems right

Answer 17

a) No one has done a one-time fling? r=0
b) At least one person r=1
c.) No more than two people \[r \ge 2\]
That's how I calculated it, whatcha think?

Answer 18

b)P( atleast 1 person) =1-P (no one )

Answer 19

no more = less
r<=2

Answer 20

oh yes. sorry.

Answer 21

exactly 1---->r=1
atleast 1 = 1- none

Answer 22

atmost 1 --> r<=1

Answer 23

make sense ?

Answer 24

Yes, I think so.

Answer 25

Can I show you what I did for another problem. I think my thought process is right. Feel free to point out any errors.

Answer 26

i will.
yes show

Answer 27

Trevor is interested in purchasing the local
hardware/sporting goods store in the small town of Dove Creek, Montana. After
examining accounting records for the past several years, he found that the store
has been grossing over $850 per day about 60% of the business days it is open.
Estimate the probability that the store will gross over $850
(a) at least 3 out of 5 business days.
(b) at least 6 out of 10 business days.
(c) fewer than 5 out of 10 business days.

p=.60
q=.40

a.)
n=5 because
"number of trials or events or no. of creatures/people on which experiment is performed "
=> In this case we have a total number of 5 days (events/trials)
at least 3 out of 5 would mean:
r>=3
To calculate this I would do P[r=3]+P[r=4]+P[r=5]

b.)
n=10
r>=6
To calculate.... P[r=6]+P[r=7]+P[r=8]+P[r=9]+P[r=10]

Answer 28

and did u get correct answer for the problem posted ?
n=7,r=1,p=0.1,q=0.9

Answer 29

and for (c)
n=10
r<5

Answer 30

all n, r selections \(\huge \checkmark\)

Answer 31

Yaaay!!!!!

For the first problem I got
a.) 0.478
b.) 0.522
c.) 0.974

Answer 32

sorry, i didn't do calculation part, i thought u had answers to verify, method is correct

Answer 33

I did have the answers =)

Answer 34

Thank you once again my friend!

Answer 35

so did they match?
welcome ^_^

Answer 36

yes sir!

Answer 37

ok :)