Question

Help with stats pls!
"The amount of money spent weekly on cleaning, maintenance, and repairs at a large restaurant was observed over a long period of time to be approximately normally distributed, with mean μ = $597 and standard deviation σ = $39.
(a) If $646 is budgeted for next week, what is the probability that the actual costs will exceed the budgeted amount? (Round your answer to four decimal places.)"
Not sure how to set up this problem.. do I find the z score first? And plug in $646 for X? If so, then do I use the "Ncdf" function on my calculator?

Answer 1

Nvm found the answer! But now need assistance with this part of the problem. " (b) How much should be budgeted for weekly repairs, cleaning, and maintenance so that the probability that the budgeted amount will be exceeded in a given week is only 0.12? (Round your answer to the nearest dollar.)"

Answer 2

Not good at stats, but though will like to see how will it be solved. @ganeshie8 may help.

Answer 3

@UnkleRhaukus and @waterineyes , can you please try to solve the above question.

Answer 4

you do 646-597 over the SD or 39. then find 1.25 for z score

Answer 5

since it says above the amount. find the p value that matches 1.25, which is .8944 then substaract that by from 1. so the prob would be .1056

Answer 6

hmm it can't be .1056? cause it's asking for a dollar amount?

Answer 7

my book says the answer is $643, just not sure how they got the answer

Answer 8

lol the question is asking you what probability, so a dollar value cant be the answer

Answer 9

but ya bascially this question u just solve off that probability graph