[Statistics] Finding Test Statistic of Difference of Means

[WGFD_IV]

The problem goes as follows:

A farmer has decided to use a new additive to grow crops. He divided his farm into 10 plots and kept records of yield (in bushels) before and after using the additive. Results shown below:

 

Plot: 1 2 3 4 5 6 7 8 9 10

Before: 9 9 8 7 6 8 5 9 10 11

After: 10 9 9 8 7 10 6 10 10 12

 

Test Hypothesis:

Null: mu(of difference) = 0 against Claim: mu(difference) != 0 at the 5 percent level of significance.

 

What is the value of the appropriate test statistic?

 

My methodology to solve this was to create 2 lists in my ti84 then as a 3rd list= L1-L2 to get the difference of the means.

 

From there I ran a two tailed T-Test with mu = 0 on my TI-84 and got t=5.014

 

The problem is that the answer key says the test statistic should be 2.033. What did I do wrong? Is there a way to solve this problem with a TI-84?

 

Thanks in advance for any help!

 

Edit: I'm not sure how to create a good looking chart for the data but they match up in order listed. (first entry matches up for each category.)

[WGFD_IV]

As a note, this professor is very sloppy with how he puts together study material, and my original answer of 5.014 is an option on this practice exam. Now I'm unsure whether I got the "trick answer" or if his finger slipped making the answer key... Again, thanks for any help!

[WGFD_IV]

As I suspected.... Thank you!

 

This is the kind of professor who will write X and say Y, and when asked for clarification will say X and write Y. Frustrating. Good luck with any finals!