Normal Distribution: Percentiles

[Blessed1]

The number of chocolate chips in a bag of chocolate chip cookies is approximately normally distributed with a mean of 1263 chips and a standard deviation of 117chips.
​(a) Determine the 26th percentile for the number of chocolate chips in a bag.
​(b) Determine the number of chocolate chips in a bag that make up the middle 95​% of bags.

I am just a little stuck on this one. I don't know how to go about entering the information into my scientific calculator. The example that I have to go by simply says use technology but I don't know how. Thanks!

 

[MarkFL]

Hello and welcome to MHB! (Wave)

Using a thread title of "probability and statistics" in our forum titled "Basic Probability and Statistics" is not what we consider a useful title. the thread title should describe the problem as stated in our rules:

Show the nature of your question in your thread title. The title of a post should be a brief and accurate description of what your question is about. Since we assume everyone needs help, usually urgently, titles such as ‘Urgent help needed’ etc. are pointless, annoying, ineffective and lazy. You should also avoid using symbols such as ? and ! excessively in a post title for reasons already given. An effectively titled post will get more views than one with a useless title. The thread title should be at least one level more specific than the forum in which you post. For example, do not title a thread in Calculus "Calculus Problem", but "Differentiation of a Function" or "Force on a Tank". Do not use $\LaTeX$ in thread titles, as this strains our server and hinders thread searches.

Now, we certainly don't expect our users to have all rules memorized prior to posting, and so I say this only to bring this policy to your attention. :D

In order to use technology to answer these questions, you need to have access to a function which numerically approximates the area under a normal distribution curve and can return raw data values given an area under the curve.

Does your calculator have such a function, and if so, what does the included documentation say about its use?