Question

The duration of routine operations in a certain hospital has approximately a normal distribution with an average of 125 minutes and a standard deviation of 15 minutes. What percent of operations last longer than 155 minutes?

Answer 1

please help!!!

Answer 2

how would you approach this?

Answer 3

I don't know... Please help

Answer 4

thats not an acceptable answer. you are taking a course, you have lesson material that you are spose to be reading. you should have at least some idea as to what might be needed. I am not asking for a CORRECT approach, but i am asking you to give your thoughts about it so that I do not have to do the thinking for you.

What would you try to do? ill correct if need be and guide you towards a more suitable approach

Answer 5

and do you have a ti83 calculator maybe?

Answer 6

I guess something with finding the mean, median, mode, range, and standard deviation? I just don't know this. And yea I do

Answer 7

lets use the calculator, itll make life simpler for us :)

Answer 8

lol okay

Answer 9

but idk what to type in

Answer 10

we want to open up the distribution menu ... its where we will find a function that we can use

hit: 2nd then VARS then pick the 'normalCDF' function

Answer 11

okay done

Answer 12

then it says lower: upper: u: o: paste

Answer 13

you should have something that looks like:

normalcdf(

waiting for inputs. we give it 4 inputs, each seperated by the (comma) button

normalcdf(low, high, mean, sd)

does this make sense so far?

Answer 14

I'm confused

Answer 15

oh good, it asks you for them, mine i had to input after knowing the format lol

Answer 16

oh ok

Answer 17

Don't be confused, take this as a opertunity to learn and thrive! :P

Answer 18

lol

Answer 19

our given information is:

average of 125 minutes
a standard deviation of 15 minutes

last longer than 155 minutes
so from a low of 155, and upper just put in a large value like 9999

Answer 20

Oh hey, we have the same smart score ._.

Off topic sorry x'D

Answer 21

okay thank you

Answer 22

what about the u

Answer 23

or the standard deviation

Answer 24

\(\mu\) is a symbol called "mu" its greek for m, for mean

\(\sigma\) is a symbol called "sigma" its greek for s, for standard deviation

Answer 25

I remember that from class yea

Answer 26

but what do I put there?

Answer 27

our given information is:

average of 125 minutes
a standard deviation of 15 minutes

last longer than 155 minutes
so from a low of 155, and upper just put in a large value like 9999

use the given information of course

Answer 28

is the standard deviation 15 minutes?

Answer 29

yes

Answer 30

but then whats the mu?

Answer 31

125?

Answer 32

mean and average are the same thing

Answer 33

mu is 125 yes

Answer 34

okay thank you

Answer 35

but i GOT .O22 and my teacher said the correct answer is 2.5%

Answer 36

hello

Answer 37

lets chk the wolf ...

Answer 38

?

Answer 39

what

Answer 40

someone please help

Answer 41

http://www.wolframalpha.com/input/?i=P%28z%3E%28155-125%29%2F15%29

2.275 is the correct, exact, answer.

Answer 42

then what did I do wrong?

Answer 43

you did nothing wrong ... you used your calculator instead of a table.

calculators are more exact

Answer 44

then is my answer (.022) correct?

Answer 45

its correct yes; it is not an approximation it is exact

Answer 46

well, its sorta an approximation, but its better than 2.5

Answer 47

then how come my teacher said the answer is 2.5%

Answer 48

I'm confused now

Answer 49

youll have to ask your teacher that, im not your teacher

Answer 50

lmao

Answer 51

okay well thank you anyway

Answer 52

good luck