Here's the question you clicked on:
miss_karina
The average time between incoming calls at a switchboard is 4.5 minutes. The probability of waiting less than t minutes for next incoming call is approximated by the model F(t) = 1 −e^-t/4.5 If a call has just come in, ﬁnd the probability that the next call will come within a) .51minutes So do I just plug in .51 minutes in to t? If I do so I get a decimal and it doesn't seem right. Please help explain this.
thats what it says, thats what i would do
i guess you have to change 51 minutes to a decimal first
oh no you don't, it says .51 minutes, so just plug it in
i get about .107 seems reasonable https://www.wolframalpha.com/input/?i=1+%E2%88%92e^-%28.51%2F4.5%29
as long as you get a number between zero and 1 it is a probability, and you would imagine that this one would not be too large because the average is 4.5
yes that is what I got! .107 I wasn't sure but thank you so much for your explanation