So I got this question wrong on a recent quiz but we are not allowed to see what the correct answer. I emailed my professor and all he did was give me a basic hint. I have added the z score tables we had to refer to, along with parts of the other questions I had correct that partially relate to the question I got wrong.

QUESTION 1: Got this correct

Sample Mean = 1.02

Sample Variance = 0.23

Sample Standard Deviation = 0.48

QUESTION 2: Got this correct

Assumption: Supposed we have data that comes from the normal distribution with the population mean 1.00 and population standard deviation 0.35. (we make this assumption so that we can apply what we know about normally distributed data). Provide the appropriate cuttoff values depicted below. This was the question I got correct but I wanted you to have the data.

-0.05

0.30

0.65

1.00

1.35

1.70

2.05

QUESTION I GOT WRONG!!

Suppose Ameritrade decided on a new policy concerning which trades they will monitor. (We still are assuming the trades come from a normal with population mean of 1 and a population standard deviation of 0.35.

Under new policy, Ameritrade will now monitor trades within the middle 90% of the normal distribution of scores.

Use R to provide the positive z-score that corresponds to the upper boundry of the mid-90% of the distribution:

I got this wrong part of z score wrong, and the only hint he gave me was the upper limit should be 1.58.

So basically I need to figure out the right z score on the table and also have the lower limit correct. I am very confused on how to get the upper and lower limits. Please break this down and if there is some kind of equation to figure the limits out for future reference please share. I want to learn.

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