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Mathematics 12 Online
OpenStudy (anonymous):

someone be kind enough to help? :)

OpenStudy (anonymous):

heres the question :)

OpenStudy (anonymous):

anyyyyone?

OpenStudy (anonymous):

@amistre64

OpenStudy (umarsback):

i'd help but i suck at math D:

OpenStudy (anonymous):

:/ thanks anyway :)

OpenStudy (anonymous):

@thomaster

OpenStudy (anonymous):

@modphysnoob

OpenStudy (anonymous):

@ash2326

OpenStudy (amistre64):

number of bases, divided by number of times

OpenStudy (anonymous):

each?

OpenStudy (amistre64):

the number of bases is the sum total of bases: 0(450)+1(190)+2(32)+3(10)+4(10) all out of 692 attempts

OpenStudy (anonymous):

sooo i dont divide?

OpenStudy (amistre64):

of course you do; this is a weighted average

OpenStudy (amistre64):

instead of counting out: 490 zeros, 190 "1s", 32 "2s" etc ... can multiply top to bottom to determine the total number of basses

OpenStudy (amistre64):

since it tells you the total number of attempts in the problem is 692 .... thats your divider

OpenStudy (ankit042):

E[X] = x1p1 +x2p2+x3p3...+xnpn

OpenStudy (amistre64):

which simplifies to that setup as well

OpenStudy (ankit042):

can you find p(x)?

OpenStudy (anonymous):

im soo confused :(

OpenStudy (amistre64):

\[\frac{0(450)+1(190)+2(32)+3(10)+4(10)}{692}\] \[\frac{0(450)}{692}+\frac{1(190)}{692}+\frac{2(32)}{692}+\frac{3(10)}{692}+\frac{4(10)}{692}\] \[0\frac{450}{692}+1\frac{190}{692}+2\frac{32}{692}+3\frac{10}{692}+4\frac{10}{692}\]

OpenStudy (ankit042):

can you tell what is probability of hitting 0?

OpenStudy (amistre64):

since the weighted average is simpler to compute; id just go with it

OpenStudy (anonymous):

so i add 450 + 190 + 32 + 10 + 10 ?

OpenStudy (amistre64):

not according to the format i presented ....

OpenStudy (amistre64):

but then thats just adds to 692

OpenStudy (anonymous):

thats why i asked, what am i supposed to do first then?

OpenStudy (amistre64):

no need to, they already give you that information in the problem setup

OpenStudy (ankit042):

@dianadelucio you know what Expectation is?

OpenStudy (anonymous):

@ankit042 sort f yea.

OpenStudy (anonymous):

of

OpenStudy (amistre64):

lol, thought maybe that was a swear word :)

OpenStudy (anonymous):

haha nooo, why would i swear when you guys are trying to help me lol @amistre64

OpenStudy (ankit042):

haha I hope it was not the other f :P anyways . E[x] = x1p1 +x2p2+...+xnpn Now from the table you can easily find probability of different events

OpenStudy (amistre64):

he gets 324 bases out of 692 hits

OpenStudy (ankit042):

p(0) = 450/692

OpenStudy (anonymous):

what does that meann? E[x] = x1p1 +x2p2+...+xnpn

OpenStudy (amistre64):

i broke down ankits method from the weighted average im using .... i beleive i did it correctly that is

OpenStudy (anonymous):

sooo.. what am i supposed to do with the equation?

OpenStudy (ankit042):

let me quote from Wikipedia "Expected value refers to value of a random variable one would "expect" to find if one could repeat the random variable process an infinite number of times and take the average of the values obtained."

OpenStudy (amistre64):

the expected value formula is a "simplification" of the weighted average since itll take extra steps to determine the probabilities of all the hits, i suggest just taking the weighted average approach is all

OpenStudy (anonymous):

and how do i find that?

OpenStudy (amistre64):

\[\frac{\#bases}{\#at-bats}\] \[\frac{0(450)+1(190)+2(32)+3(10)+4(10)}{692}\] \[\frac{324}{692}\]

OpenStudy (amistre64):

its the same method of been doing since the start :)

OpenStudy (amistre64):

reduce the top and bottom as needed

OpenStudy (ankit042):

So in our sample space events(x) are 0,1,2,3,4 now we know the likelihood of an event(probability) from the table

OpenStudy (anonymous):

81/173 ?

OpenStudy (amistre64):

thats what i get, yes. it just seems weird in context to me ....

OpenStudy (amistre64):

on average, he gets 81/173 bases per hit

OpenStudy (ash2326):

yes, correct

OpenStudy (amistre64):

the probability of him getting to a base is about 46%

OpenStudy (anonymous):

thank you ! @amistre64 @ankit042 @ash2326 :)

OpenStudy (amistre64):

youre welcome, and again ... good luck :)

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