Statistics: Assessing T-tests

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Assessing T-tests
To clearly identify what a t-test accomplishes in descriptive statistics it is imperative to understand what a t-test represents. A “t-test is a parametric statistical test for comparing the means of two independent samples” (Plichta & Kelvin, 2013, p. 464). Gosset developed the t-test for use in quality control at the Guinness Brewery and published his works under the pen name “Student” (Plichta & Kelvin, 2013). T-tests use assumptions related to the underlying variable of study, where it is assumed that the underlying variable is distributed normally (Fagerland, 2012, p. 76). In essence, the t-test examines differences between two groups on a variable of interest. Research Study Review

Bradley (2012), proposed to study the effects of nurse practitioners (NP’s) utilizing a skin cancer screening tool along with receiving further education on skin cancer assessment and diagnosis. The study was predicated on the Health Promotion Model (HPM), which was selected based on it relevance to the practice of NP’s and their duty to promote healthy behaviors (Bradley, 2012). “Evidence-based research showcased within the HPM can aid NPs in making practical recommendations to reduce skin cancer risk, specifically melanoma” (Bradley, 2012, p. 83). Study participants (NP’s) were provided with training and educational programs to increase their knowledge and subsequent assessment skills and documentation of physical skin assessments for patients. “The HPM was used in this study to examine the health status and health promotion behaviors of young adults with respect to screening for melanoma” (Bradley, 2012, p. 83). The study was conducted in two phases where “phase one utilized a quasi experimental design to examine characteristics of a single sample of NPs exploring the aspects of skin cancer screening phenomena among them in a single college health center setting” (Bradley, 2012, p. 83). NP’s were given a pre and post test to ascertain their cognitive processes and the changes in the ability to document properly based on the education they received (Bradley, 2012). “In quasi-experiments, the researcher does not have the ability to randomly assign the participants or ensure that the sample selected is as homogeneous as desirable” (Levy & Ellis, 2011, p. 155). NP’s attitudes were also evaluated after receiving the educational component to determine if attitude changes were elicited (Bradley, 2012). The study revealed an increase of correct documentation of skin cancer screening and education related to skin cancer (Bradley, 2012). Study Variables and Statistics

The study utilized a convenience sample of six certified NP’s who ranged in age from 40-64 (Bradley, 2012). Convenience sampling chooses samples that are readily available, this type of sampling can possess bias due to a lack of a statistical method of choosing the sample (DiCalogero, n.d.). The NP’s were given a Didactic skin cancer pre and post test, which consisted of 16 questions using a multiple choice format used to evaluate cancer knowledge and recognition (Bradley, 2012). “Test-retest reliability was r = .90, no alpha was given” (Bradley, 2012, p. 84). A program evaluation questionnaire using a Likert Scale was given following the post test to assess the NP’s attitudes, knowledge and perceptions related to relaying the skin cancer data and future participation in skin cancer screening for the public using a five point scale (Bradley, 2012). NP’s were also asked to use the screening tool for documentation via a pictorial display to document lesions and note patient education given (Bradley, 2012). Data collection transpired over a 30-day period. “Prior to the education, 30 randomly selected de-identified charts were retrospectively reviewed for skin cancer screening documentation” (Bradley, 2012, p. 85). At the conclusion of the study 22 additional charts were audited to note if improvement in the skin...
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