Question

Let X~B(6, 0.35). Find the median. I found it to be 1.5, but apparently its 2? Why?

Answer 1

@satellite73 ?

Answer 2

i have no idea
what does any of this mean?

Answer 3

X is binomial random variable?

Answer 4

need more info dear my dear

Answer 5

i think it is floor right?

Answer 6

or ceiling?

Answer 7

it is an integer in any case, so it cannot be 1.5

Answer 8

no idea lol
thought this is statistics question

Answer 9

\[6\times .35=2.1\] so must be floor

Answer 10

@xapproachesinfinity @satellite73 this is a stats question

Answer 11

my book just says let X~B(6, 0.35). i think this is a discrete variable dist

Answer 12

@satellite73 what do you mean?

Answer 13

a quick google search tells me it is \[\lfloor np \rfloor\]

Answer 14

what does floor mean? Im confused

Answer 15

i.e the greatest integer less than or equal to \(np\)

Answer 16

i love google

Answer 17

greatest integer function
greatest integer less than or equal to the number

Answer 18

but what is the median though?

Answer 19

so for example like here
\[\lfloor 2.1\rfloor=2\]

Answer 20

what rule is that?

Answer 21

that is what it is for a binomial
the greatest integer less than or equal to \(np\)

Answer 22

look on the right under "median"
http://en.wikipedia.org/wiki/Binomial_distribution

Answer 23

oh ok. so since np=2.1, median has to be 2 although it is technically 1.5?

Answer 24

how would you do this then: P(X<4|X>2)

Answer 25

what do you mean " it is technically 1.5"?

Answer 26

because median is max value for f(x)<=0.5 and min value for f(x)=>0.5. i drew out a table and calculated the values to be 0.319 and 0.647.

Answer 27

i think (wouldn't bet the ranch on it though) that that is the mean, not the median

Answer 28

mean is 2.