Microsoft Office Tutorials and References

In Depth Information

You now need to compute the values of the above formulas in the following

cells:

D13: the result of the formula needed to compute cell B13 (use 2 decimals)

D16: the result of the formula needed to compute cell B16 (use 2 decimals)

D19: the result of the formula needed to compute cell B19 (use 2 decimals)

D22:

¼

SQRT(D19) (use 2 decimals)

This formula should give you a standard error (s.e.) of 1.98.

D25: 1.96 (Since df
¼
n1
þ
n2 – 2, this gives df
¼
109 – 2
¼
107, and the

critical t is, therefore, 1.96 in Appendix E.)

D28:

(D4–D5)/D22 (use 2 decimals)

This formula should give you a value for the t-test of:

¼

4.55.

Next, check to see if you have rounded off all ﬁgures in D13: D28 to two decimal

places (see Fig.
5.11
).

Now, write the following sentence in D31 to D34 to summarize the result of the

study:

─

D31: Since the absolute value of

─

4.55

D32: is greater than the critical t of

D33: 1.96, we reject the null hypothesis

D34: and accept the research hypothesis.

Finally, write the following sentence in D36 to D38 to summarize the conclusion

of the study in plain English:

D36: Overall, females rated the quality of Biology 101

D37: this past semester as signiﬁcantly better than

D38: males (64 vs. 55).

Save your ﬁle as: BIOL12

Important note:
You are probably wondering why we entered both the result and

the conclusion in separate cells instead of in just one cell. This is because if you

enter them in one cell, you will be very disappointed when you print out your ﬁnal

spreadsheet, because one of two things will happen that you will not like: (1) if you

print the spreadsheet to ﬁt onto only one page, the result and the conclusion will

force the entire spreadsheet to be printed in such small font size that you will be

unable to read it, or (2) if you do not print the ﬁnal spreadsheet to ﬁt onto one page,

both the result and the conclusion will “dribble over” onto a second page instead of

ﬁtting the entire spreadsheet onto one page. In either case, your spreadsheet will

not have a “professional look.”

Print this ﬁle so that it ﬁts onto one page, and write by hand the null hypothesis

and the research hypothesis on your printout.

The ﬁnal spreadsheet appears in
Figure 5.12
.

Now, let’s use the second formula for the two-group t-test which we use

whenever either one group, or both groups, have a sample size less than 30.

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