Independent t test

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Independent t test
Elisha Kennedy, Natalie Eberhart Doug
Lobdell Brittney Hendrix

• Using Relaxation Techniques and Positive
  Self-esteem to Improve Academic Achievement of
  College Students

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Background Information
Patten, Mildred L. Education Psychological
Research, Article 27 Using Relaxation
Techniques and Positive Self-esteem to Improve
Academic Achievement of College Students. pgs.
149-150. 1995
The purpose of this study was to examine whether
muscle relaxation increased exam scores of
college students compared to students who did
not use muscle relaxation.
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Research Question Statistical Hypotheses

• Does there appear to be sufficient evidence to
  conclude with at least 95 confidence that the
  mean Final grade for students taking a muscle
  relaxation class is higher than the mean for
  students who do not take the muscle relaxation
  class?
• H0 µr- µclt0 H1 µr- µcgt0

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Raw Data
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Decision Rule

• Given N120, N220, df38, alpha level.05,
  upper tail critical
• Reject H0 if calculated t gt 1.697

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Descriptive Statistics
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Calculations
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Decision

• Reject H0 with at least 95 confidence since
  calculated t1.68 is gt 1.697, within rounding.

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Interpretation

• Yes, this study does provide sufficient evidence
  to conclude with at least 95 confidence that
  muscle relaxation classes increased final
  examination scores for college students.
• t(38)1.68, p.05 (one-tailed), r2.07 (small
  effect size)
• The average final examination score for the
  relaxation students was 75.70 (SD9.64) compared
  to the average final examination score for
  non-relaxation students of 70.80 (SD8.74). The
  difference between these means is not large
  enough to confidently conclude a difference.
• The 95 confidence interval around the difference
  between the two group means is 3.91 to 15.69,
  which does not include 0.

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Error Bar Graph for Final Examination Scores
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Future Research

• This study would need a larger sample size since
  our calculated t was just barely in the rejection
  area.
• See if there is a difference between male and
  female students or university size.

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Conclusion

• This study also gave us results for midterm
  grades and the results were the same.