Please use the following files to do an Excel !
|Questions from Assignment||From Example||Notes for Assignment|
|a) Write down the null and alternative hypothesis (Ho and Ha)..||Ho: µ=3 pounds||But for assignment we are interested in whether population average is larger|
|Ha: µ<3 pounds||In some way make sure you mention average of the population|
|b) What are the n, x-bar and sigma?||n=36; x-bar=2.92; sigma=0.18||In assignment, sigma is given. Use Excel to get x-bar and n|
|c) Compute P-value based on the sample.||Calculated z=-2.67 and found area to left using table A||For the assignment we need the area on the ….|
|d) Test the hypothesis at the significance level α=0.05, i.e. reject Ho or Ha Why?||We rejected Ho for Ha b/c the p-value (0.38%) was less than the alpa value (1%)||Compare the p-value to the alpha value to decide if reject Ho for Ha or not|
|What conclusion can you make about the mean weight of all packets? That is, what is the plain English conclusion?||The population average is less than 3 pounds.||State correct English conclusion based on statistical conclusion above and rule 3 discussed below.|
|We have used three very important rules.|
1. Whichever direction the symbol is pointing in Ha, that is the side of the normal curve where you find the p-value
If < , then p-value is on left
If > , then p-value is on right
Table A gives area to the left, so if need area to right, then get area from table and subtract it from 1.0
2. If the p-value is less than the alpha value, then reject Ho for Ha.
If the p-value is not less than the alpha value, then do not reject Ho for Ha.
3. The statistical conclusion is about Ho
Reject Ho for Ha or
Fail to reject Ho for Ha
The plain English conclusion is based on Ha
If statistical conclusion is reject Ho for Ha, then English conclusion is to state Ha in plain English
If statistical conclusion is that you fail to reject Ho for Ha then English conclusion is “We did not have adequate statistical eviddence to conclude” and then state Ha in plain English.