How do you solve this in a calculator....need this ASAP....10 points for right answer

c)
= P(1.05 < Z < 2.05)
= P(Z < 2.05) - P(Z < 1.05)
= φ(2.05) - φ(1.05)
= 0.9798177845 - 0.8531409436
= 0.1266768409

φ Idk what that is and i dont understand what would i do in my calculator (TI 83 Plus) to get this answer (need to know so i can pass my test)

Thanks

φ is the lowercase Greek symbol phi. And uppercase phi, Φ, denotes the cumulative distribution function of a normal distribution.

Therefore, you could just simply do:
P(1.05 < Z < 2.05)
= normalcdf(1.05,2.05)
≈ .1266769329

normalcdf( is found via [2nd][Vars](Distr) > 2:normalcdf(.

I do not know where exactly error function erf denoted by greek letter phi is located in your tex instrument calc. It can be calculated by spreadsheet on a comp like it is done at
https://spreadsheets.google.com/ccc?key=…
It is =normsdist() function there in googe docs.
Phi is cdf (Cumulative Distribution Function) of Normal Probability Distribution.
http://en.wikipedia.org/wiki/Normal_dist…
Maybe I was not precise enough when stating that it is erf, because it is shifted like it is explained at
http://en.wikipedia.org/wiki/Error_funct…
But phi sure denotes cdf of Normalized Normal Distribution with average mu=1 and standard deviation sigma=1.
If you can find erf button on your calc, use it like in formula at
http://en.wikipedia.org/wiki/Normal_cumu…

It seems that the answer is at the address
http://www.ehow.com/how_4523946_find-nor…

Instructions at
http://www.ehow.com/how_5958444_values-t…
directly solve examples like you have given.
use function: normalcdf
lower bound = 1.05
upper bound = 2.05
mean = 0
standard deviation = 1

Official reference to normalcdf is at page 426 of the document
http://education.ti.com/guidebooks/graph…
The calc picture is at
http://education.ti.com/educationportal/…

Summary.
You have to use normalcdf function (denoted by phi in your example) of your calc which is located in meny distr.

I assume that P is some function that is defined in the open interval (1.02,2.05). And they are defining an inequality with predetermined variables, are you sure that this is all the information they give you... What is your phi function?