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STREAM B ONLY: Data analysis for your Results section.

A t-test (two-tailed, assuming unequal variance) was performed on the data to test two null

hypotheses. In short, the t-test compares the means of two sets of samples (see Skills Book p. 51 and

thepdf titled Information on P values and t-tests referred to below) to see if there is a real

difference in the data that gave rise to those means.

The aim of the caffeine experiment was to determine the effect of caffeine on change in pulse

and respiration rate after exercise.

Sample A contained decaffeinated, Sample B was caffeine (stream B only).

The corresponding null hypotheses being tested (and their alternate hypotheses) are

1. HO: There is no significant difference in the mean change in pulse rate between subjects thatconsumed caffeine (treatment) and subjects that did not consume caffeine (control).

HA: There is a significant difference in the mean change in pulse rate between subjects that

consumed caffeine (treatment) and subjects that did not consume caffeine (control).

2. HO: There is no significant difference in the mean change in respiration rate betweensubjects that consumed caffeine (treatment) and subjects that did not consume caffeine

(control).

HA: There is a significant difference in the mean change in respiration rate between subjects

that consumed caffeine (treatment) and subjects that did not consume caffeine (control).

Important documents for you to read:

Caffeine Report instructions (Lab Manual) for where to put these statements. Appendix VI (Lab Manual) for construction of graphs in Excel and the addition of range bars. The pdf titled Information on P values and t-tests. The Skills Book has more details on hypotheses (p. 42).The last two documents can be found in the Report folder (in the Assessments folder)

The combined class raw data file is available on Blackboard (Report folder) for you to complete the

Results section. The summary Table from the t-tests is also available in this file (see tabs at the

bottom of the Excel page) for you to include in the Appendix.

The significance level of the test is 0.05, i.e. if the probability (P-value or P (T

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Copy these statements into the appropriate part of your Results section.

The mean change in pulse rate of subjects that consumed caffeine was not significantly different

from that of subjects that did not consume caffeine and therefore the H O was accepted (t=1.5,

d.f.=109, P>0.05).

The mean change in respiration rate of subjects that consumed caffeine was not significantly

different from that of subjects that did not consume caffeine and therefore the HO was accepted

(t=0.8, d.f.=89, P>0.05).

(See Appendix 1 for raw data, hypotheses and summary Table of the t-tests)