Stats Help

[higgsbreanne]

I am struggling with finding the probability. If you look at the screenshot below, I am able to almost complete section c and d, however, I do not know how to figure out the probability values. When I asked someone for help, they said that they used an x-value chart. I don't know what means. Is there a trick or an equation? Thank you!

 

[blamocur]

Are you familiar with CDF for normal distribution (https://en.wikipedia.org/wiki/Normal_distribution#Cumulative_distribution_function)?
Your [imath]p (z < a)[/imath] in 2.a is the definition of the CDF [imath]\Phi(a)[/imath] from the page referenced above. The question is how can you compute [imath]\Phi[/imath]? Are you supposed to use a calculator? A programming language on a computer?

 

[Harry_the_cat]

, they said that they used an x-value chart.

Do you mean a z-value chart?