Week 5 CI Homework

This homework is based on the Confidence Interval example I went over in class.  Here is the link to the Google Sheet Links to an external site..  Make a copy of that sheet and look at the CI tab. 

I explained in class that an alpha-sort is an informal way to grab random (ish) samples, so for the homework,

1. Create a sample where the first letter of your first name (or nickname) matches the first letter of runners.  So Allyson does the "A" runners, Bill the "B" runners, and so on.  (You will probably have about 10 or 20 or so in your sample.)  

2.  Use Google Sheets or Excel to calculate the following using a 90% confidence interval. 

 X-BAR (sample mean) 
SD (same standard deviation)

n (sample size)
df (df=n-1)
CL = 1 - a    
a =    10%
a/2 =    0.05
t.inv(a/2, df) 
SD/SQRT-n  
EBM       
X-BAR + EBM   
X-BAR - EBM    

3. State the range for the confidence interval.  For example, "90% confident that mean is between 31 and 35" (in class example).  

Submit your work as via Excel or Google Sheets.