**EDIT: I am having trouble uploading my .xls file. I also tried putting the .xls into a .zip but I will always receive an error message. How can I solve this?**

I am a college student and have just started my first class of statistics. I am quite good at math (taking calculus) but I am struggling to understand what exactly the Z-Score means and how to compute the average z-score.

My problem is specifically:

I have 254 (n=254) closing prices of the Microsoft Stock (MSFT from yahoo finance) in an excel spreadsheet. I have computed the mean, mode, median, stdev as well as Q1,Q2,Q3 and P90, P50,P10 as well as a few other things (The .xls file is attached)

Column H is where the problem is:

According to my notes, the zscore is computed by Z = (x-mean)/standard deviation. However, what exactly is x? If i want to compute Z1 do I take the first stock price, subtract the mean from it and then divide by the STDEV?

Also, if n=254, will I have 254 Zscores?

I hope these questions are not considered stupid, I am really trying to understand this.

This project is due in about 2 weeks and I have finished the majority of it, but the zscores are throwing me off.

Any help is greatly appreciated!

Thanks in advance!

Kind regards,

sectas