Thread: I don't get these questions... x_x

Sorry for plaguing you guys with questions lately. But the teacher won't let me drop the advanced maths classes until next term. :[

c. Explain why the distribution of the Z variable is normal, with a mean of 0 and a standard deviation is 1.

(Do I say something like, "We needed to solve a value to standard deviations?")

d. Calculate Pr(Z>1.4) [By the way, the > has an underline underneath it]

(What do I calculate it with? What's the probability that I'm supposed to calculate with? I don't get it...)

e. Calculate k if Pr(Z<k) [Again, the < has an underline.]

(And again, I don't get it D

Originally Posted by Hikaru

Sorry for plaguing you guys with questions lately. But the teacher won't let me drop the advanced maths classes until next term. :[

c. Explain why the distribution of the Z variable is normal, with a mean of 0 and a standard deviation is 1.

(Do I say something like, "We needed to solve a value to standard deviations?")

d. Calculate Pr(Z>1.4) [By the way, the > has an underline underneath it]

(What do I calculate it with? What's the probability that I'm supposed to calculate with? I don't get it...)

e. Calculate k if Pr(Z<k) [Again, the < has an underline.]

(And again, I don't get it D

Question D: You want to calculate the probability of a Z-Score. 1.4 is your Z-Score.

Go here for the math:
Probability of a Random Variable in the Normal Distribution

Press P(X>Z) and then enter 1.4 where it tells you to and press Calculate Normal Distribution Probability.

Also, you can use Excel: =1-NORMDIST(1.4,0,1,TRUE)

We do 1 - because that covers the area of curve from the far left region all the way up to your z-score. So you want everything after that.

Following that logic for e, your answer is 1 - P(Z<k)

Read up more on Z-scores for the business sense of things.