Question

PLZ HELP!!! will give medal and become fan!!
Rumor has it that a woman can drink blueberry tea to increase the likelihood of having a girl baby to three times that of having a boy.
a) If a woman drinks the tea daily what are the chances that, out of five children, there are at least 2 girls?
b) What is the expected number of girls in 5 children?

Answer 1

@TheSmartOne @mathstudent55 @agent0smith
I dunno, sorry :c

Answer 2

'rumour has it' is not a statistical statement.

The chances of having a girl are approximately the same as having a boy, regardless of the rumour

Answer 3

yea but how would u solve it?

Answer 4

if you assume the probability of girl = possibility of boy then this is th esame as tossing a coin

you are studying combinations and permutations

look up the formula for tossing at least 2 heads from 5 throws.

That is the correct answer

(HOWEVER my guess is that the question expects you to accept the ridiculous rumour...)

Answer 5

we did learn combination and permutation but we are learning probability distributions right now so..

Answer 6

they are linked

this is binomial probability

Answer 7

"chance of a girl baby to three times that of having a boy"
so
chance of a girl must be 0.75, chance of a boy 0.25

a) If a woman drinks the tea daily what are the chances that, out of five children, there are at least 2 girls?

It's binomial probability. Hopefully you're familiar with it.
\[\Large P(X = r) = \left(\begin{matrix}n \\ r\end{matrix}\right) p^r q^{n-r}\]p=0.75
q=0.25
n=5
You need to find \(\large P(X \ge 2)\)

You can use some things to simplify the work\[\large P(X \ge 2) = 1 - P(X \le 1)\]where\[\large P(X \le 1) = P(X=0) + P(X=1)\]

Answer 8

I stress again

'rumour has it' does NOT state the Pg=3Pb

Answer 9

Lots of questions ask us to accept some nonsense and use it anyway.

Answer 10

so would r=3 then solve for p(x=3)

Answer 11

Depends what you're doing. If you're doing \[\large P(X \ge 2) = P(X=2) +P(X=3) +P(X=4) +P(X=5)\]then yes. But hopefully you see why that is more work than finding \[\large P(X \ge 2) = 1 - P(X < 2) \]or\[\large P(X \ge 2) = 1 - [P(X=1)+P(X=0) ]\]

Answer 12

oh okay makes sense thanks alot !!! u helped alot

Answer 13

how about b)

Answer 14

Really easy.
b) What is the expected number of girls in 5 children?
Multiply probability of a girl by the total children.

Answer 15

nvm i got it

Answer 16

thank you