Today's local newspaper lists 20 stocks of local interest. of those stocks ten increased five decreased and five remained unchanged yesterday. if wwe decide to buy two of stocks what is the likelyhood that both increased yesterday?

P(x=2) = 0.2368

Step-by-step explanation:

given data

stocks of local interest N = 20

stocks increased K = 10

stocks decreased =  5

remained unchanged = 5

solution

we take here no of stock that are increased randomly n = 2

so here Hypergeometric random variable can take integer value

{max(0, n+k - N ), min(n,K) } = {0,2}

so here

P(x=2)

so

P(x=k)  =      .......................1

P(x=2 ) =    

solve it we get

P(x=2 ) = 0.236842

now we use excel function as

HYPGEOM.DIST (k,n,N.cumulative)   .....................2

so it will be

HYPGEOM.DIST (2,2,10,,false)

we get

HYPGEOM.DIST (2,2,10,,false)  = 0.236842

so

P(x=2) = 0.2368

proportions are fractions that equal to each other. so if two fractions are the same, they are proportional.

let's check the answers to see if they are proportional.

question a is not proportional because you can't turn 1.5/3 to 3/9. if you try to multiply 1.5/3 by 2 or 3, you wont get 3/9. it's impossible to make the fractions the same.

question b is not proportional because you can't turn 22/33 to 4/6. 33 can't go into 6.

question c is proportional because when you multiply 2 and 3 by 71, you would get 142/213, and those fractions equal to each other

question d is proportional because when you divide 14 and 7 by 2, you would end up with 7/3.5, and those fractions equal to each other.

the answer is: -22 also a

hope i

-lavira: )