Transcript Inferential statistics, cont`d., Reading, writing, and

Single sample
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One-tailed versus two-tailed tests
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t-test:
Use
Significance level (type I and II errors)
Degrees of freedom (df)
Two samples
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Unpaired or independent samples t-test
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Paired or dependent samples t-test
Non-parametric statistics
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Chi-square Test (χ2): Used with nominal variables in two
independent categories
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Works by comparing the actual scores to probability estimates
Rank-order methods: Scores transformed into ranks
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Wilcoxon matched-pairs signed ranks test: For dependent
samples
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Mann-Whitney U test: For independent samples
Multigroup statistical methods
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ANOVA (Analysis of Variance)
 Saves time
 Reduces probability of significance by chance
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Rationale: Between group and within group variance
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Is variability between groups > variability within groups
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Statistic: F ratio and df
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One-way ANOVA: Similar to independent samples t-test
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Two-way ANOVA: Two independent variables
 Two main effects and one interaction
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Multiple comparison methods: Post-hoc tests
 Scheffe (unequal sample size)
 Tukey (equal sample size)
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Randomized blocks ANOVA (RBANOVA): For repeated
measures designs
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Analysis of covariance (ANCOVA): Controls for variables
that might affect data
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Non-parametric multigroup tests
 Friedman two-way analysis of variance
 Kruskal-Wallis one-way analysis of variance
Complex statistical methods
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Multivariate ANOVA (MANOVA): More than one
dependent variable
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Discriminant analysis: Estimates the contribution of each
dependent variable in separating groups.
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Factor analysis: Organize observations into underlying
constructs
Research proposal outline
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Title
Abstract
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Table of contents, budget, resources, biographical
sketches
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Research protocol
 Specific aims
 Background and significance
 Methods
 Ethical issues: IRB
References
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Title page
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Title: Short, succint, unambiguous.
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“A study to investigate physiological measures of
anxiety and their relation to stuttering adaptation
during oral reading trials under two levels of audience
complexity”
Investigator details (degree, affiliation, contact)
 Agency to which being submitted
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Abstract
 100-200 words
 Summary of proposed research
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Budget: Equipment, subject payments, salaries, travel,
consultants, administrative costs.
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Biography: Education, skills, abilities. Resume, pilot
studies, completed investigations, existing grants.
Research protocol
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Specific aims: Objectives, rationale
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Background and significance: Existing knowledge,
Priliminary work, Theoretical and practical consequences,
Clinical applications.
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Methods: Sampling, subjects, measurements,
procedures, data analysis.
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Ethical issues: IRB, human/animal subjects protection
References
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Appropriate citations
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Watson, Jensen, Smith, and Kelly (1987)
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Watson et al. (1987)
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(Miller, 1991)
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(Miller, 1991; Killion, 1992)
Complete references.
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Author (year). Title. Ear and Hearing, 36, 776-781.
Writing
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Concise, clear, efficient, effective
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“ The results of the study indicated that when faced with
hyperactive children with short attention spans (AD-HD) who were
clearly unmotivated and who eventually became unresponsive to
test stimuli because of their distractibility, clinicians were prone to
modify their instructional techniques by terminating reinforcement
followed by the introduction of a “time out” phase, during which
time the training program was suspended for a period of few
minutes or more.”
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When the rate of the response being trained decreased by 10%, the
clinicians suspended the training program for 5 to 10 minutes.
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Resources: APA, AIP