Table of Contents

• Testing differences
• 1: How to convince your boss
• 2: Looking at the data
• 3: Is the average different?
• 4: How big is big?
• 5: How to combine SDs
• 6: Combining SDs for fun and profit
• t-calc and t-crit
• 7: Getting to t-calc
• 8: A formula for t-calc
• 9: Degrees of freedom
• 10: The bottom line (finally)
• Putting it all together
• 11: Give it a try
• 12: Once more for luck
• 13: The big picture

Once more for luck

And how does Fish-2-Whale compare to MalWart? See if you can do the steps on your own, just using the sample sizes, average, and SD.

	n	average	SD
MalWart Brand	6	192 g	15 g
Fish-2-Whale	6	267 g	44 g

 

degrees of freedom (df)	tcrit (for p-value = 0.05)
1	12.7
2	4.3
3	3.2
4	2.8
5	2.6
6	2.5
7	2.4
8	2.3
9	2.2
10	2.1
20+	2.0

So, are the two brands different, statistically speaking?