A contractor is required by a county planning department to submit one, two, three, four, or five forms (depending on the nature of the project) in applying for a building permit. Let Y=the number of forms required of the next applicant. The probability that y forms are required is know to be proportional to y, that is, p(y)=ky for y=1,...,5.

(a) What is the value of k?
(b) What is the probability that at most three forms are required?
(c) What is the probabilty that between two and four forms (inclusive) are required?
(d) Could p(y)=y^2/50 for y=1,...,5 be the pmf of Y?

a) c = 1/15

b) =2/5

c) = 3/5

d) No, it cannot be the PMF of y.

Step-by-step explanation:

We have that

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explanation

the graph has a slope of 1/3 because each time you move up 1, you go to the right 3. so, slope = rise/run = 1/3. we can cross choice a off the list since we want a slope of 3, rather than 1/3.

the first table shown has a slope of -3. this is because the rise is -6 and the run is 2, so slope = rise/run = -6/2 = -3. note how x increases by 2 each time (run) and y drops by 6 each time (rise). choice b can be eliminated.

the second table has a slope of 3. each time x goes up by 1, the y values increase by 3. slope = rise/run = 3/1 = 3. alternatively you can use the slope formula to prove that the slope is 3 here. use any two rows of values to generate the two points. choice c is one of the answers

the third table also has a slope of 3. let's use the slope formula to prove as such. i'm going to use the first two rows of the table. so i'll use the two points (2,1) and (5,10)

m = slope

m = (y2-y1)/(x2-x1)

m = (10-1)/(5-2)

m = 9/3

m = 3 so we get a slope of 3

choice d is the other answer