## anonymous one year ago Suppose x is a normally distributed random variable with mean = 30 and standard deviation = 8. Find the value of the random variable, call it x(0), such that a. P(x>=x(0) = .5 b. P(x < x(0) = .025

1. amistre64

and what do you have to work with?

2. amistre64

and every stats student should know what the random variable for half of a normal distribution is ...

3. anonymous

What do you mean by that? I believe that is all that is provided in the problem

4. amistre64

i am not taking your course, so I do not know what you have at your disposal to work with .... the information is beside the point.

5. amistre64

ti83, or tables, or what?

6. anonymous

Oh, I see. The problem and my teacher doesn't specify. I'm not sure what method to use, but I guess by regular and calclulator methods work

7. amistre64

do you have a stats calculator?

8. anonymous

Yea a ti-84

9. anonymous

How would I show my work though?

10. amistre64

can you find the distribution menu?

11. anonymous

Yea I think so

12. amistre64

well, you show your work by writing down the process you took to get the answer. i used this function and inputed this information, and got these results ...

13. amistre64

you want what is called: INVNORM

14. anonymous

ok i see invnorm

15. amistre64

we will also prolly want to use the z formula, becuase all the invnorm function does is give us a zscore $z=\frac{x-mean}{sd}$ since we are looking for x, we algebra it into $x=mean+z(sd)$ given that z is the result of the invnorm function

16. amistre64

a. P(x>=x(0)) = .5 invnorm(.5), hit enter b. P(x < x(0) = .025 invnorm(.025), hit enter

17. anonymous

Ok I see, thank you

18. amistre64

seeing that they give you the mean and sd x = 30 + 8z