Excel 2007:

Toolkitpak Installation sequence:

CLICK GO:

2007 T Test:

• Go to the DATA ribbon
• Select the DATA ANALYSIS MENU (below)

• Select the data ranges and set the alpha (critical P) level:

Excel 2007 results sheets:

Writing a conclusion:

The results of the dependent t-test can be seen in the resultant table. The value of t (t Stat) is -4.53744, which we can round off to -4.54.

The probability of this result being due to chance can be read from the table as 0.000291 (two-tail) which means that this result is significant at the .0003 level.

We will set our alpha level as .05, so we will say that p < .05 rather than that p = .0003.

We could also look up the t critical value or cut-off value for t from the table by looking at t Critical one-tail which is 2.110 without using the spreadsheet.

We now have all the information we need to complete the six step statistical inference process:

1. State the null hypothesis and the alternative hypothesis based on your research question.
   Null hypothesis: There is no significant difference between the height of the two samples of snail shells.
   Alternative hypothesis: There is a significant difference between the height of the two samples of snail shell.
   
2. Set the critical P level (also called the alpha level )
   P=0.05
   
3. Calculate the value of the appropriate statistic. Also indicate the degrees of freedom for the statistical test if necessary.
   t = -4.53
   df = 17 (unpaired , unequal sample variance)
4. Write the decision rule for rejecting the null hypothesis.
   Reject null hypothesis since t is <= -2.110
5. Write a summary statement based on the decision.
   Reject null hypothesis , p < .05, two-tailed
6. Write a statement of results in standard English.
   There is a significant difference between the height of snail shells in the two samples.