Question

Which of the following expressions entered into a graphing calculator will return the probability of success by the 3rd event of a geometric experiment when the probability of success during a single event is 0.91?

A. geometpdf(0.91, 3)
B. geometcdf(3, 0.91)
C. geometcdf(0.91, 3)
D. geometpdf(3, 0.91)

Answer 1

(I don't really get how to solve this on a ti-84 because its asking for P: , and an X value and the only number I have is 0.91, thanks!)

Answer 2

you are also given 3

Answer 3

if you press
2nd Vars F: geometpdf( probability, n )

Answer 4

ok i entered it, it gave me .99 on the first one and an error on the second so ill do that again

Answer 5

I'm getting errors on all of them now I'm not sure why

Answer 6

pdf = a SINGLE probability

cdf = sum of more than one probability

the 'c' in cdf stands for cumulative, so that's one way you can remember the difference

Answer 7

ok so it is going to be a pdf

Answer 8

yes

Answer 9

notice how perl provided you the template

Answer 10

of how to use the geometpdf function

Answer 11

the first number you plug into the "geometpdf" function is the probability given

the second number is the value of n

Answer 12

yea i got the probability is 0.91 and the other number n=3 but when I'm entering it into my calculator its giving me an error message

Answer 13

you should have geometpdf(0.91, 3)

Answer 14

Ok now its saying (0.91,3) is .007371

Answer 15

yeah got the same

Answer 16

so that's kinda curious why it gave you an error

Answer 17

yea i answered with that but i got it wrong, the right answer was cdf(0.91,3)

Answer 18

it asks "when the probability of success during a SINGLE event is 0.91? "

it's not asking for a cumulative probability

Answer 19

so there's a contradiction going on here

Answer 20

yea its strange