What are the data saying?
Amber L. Morgan
Grand Canyon University: DNP 830
February 4, 2021Introduction
Research studies often record quantitative data results. Interpreting this data is very
important to fully unde
...
What are the data saying?
Amber L. Morgan
Grand Canyon University: DNP 830
February 4, 2021Introduction
Research studies often record quantitative data results. Interpreting this data is very
important to fully understand the results and how they impact the research question. Viewing raw
data often does not demonstrate the true meaning. Statistical analysis of the collected data can
help provide a proper understanding of what the data are saying. Statistics takes the individual
pieces of information, performs analysis depending upon the desired results, and are often
displayed in a table, chart, or graph form. This paper aims to review varying statistical analysis
methods utilizing a sample database.
Statistical Tests
Paired Sample T-Test
A Paired Sample t-etst compares two means from the same sample to determine if there is
a significant difference. This test is often used in studies containing designs such as pretest/posttest, control/experimental, or samples from the same subject on different sides. Paired Sample ttests help compare the difference between two points in time, two conditions, two measurements,
or a matched pair. This test is a parametric test and cannot be used on unpaired data, more than
two units, not normally distributed data, or a ranked outcome. In this example, baseline weight is
compared to intervention weight to determine if a significant difference exists for all that partook
in the study. This test will examine a change in weight for both the intervention and nonintervention groups. The mean baseline weight is calculated at 217.5 pounds with a standard
deviation of 53.40, and the intervention weight is 178.3 pounds with a standard deviation of
44.88. The results include t=7.188 with df=29, t(df)=2.05 with a 95% confidence interval and
p=0.000. A p<.005 indicates a statistically significant difference.
Independent Sample T-Test
2An Independent Sample t-Test is a parametric test that evaluates whether two populations
have the same mean on a given variable (Kent State University, 2021). This test is often used to
assess the differences between the means of two groups, the means of two interventions, or the
means of two change scores (Kent State University, 2021). Data must contain a continuous
dependent variable, a categorical independent variable of two groups or more, include unrelated
subjects in the various groups, use a random sample with a normal distribution of the dependent
variable, approximately equal variances across groups, and no outliers. Typically, each group
should contain a minimum of six participants and have the same number of subjects in each
group. In the example, this test was chosen to evaluate the differences between the two
intervention groups' mean weight. The results include intervention mean weight of 218.3 pounds
with a standard deviation of 53.84 and baseline mean weight of 216.7 pounds with a standard
deviation of 54.8, p=0.934, and t(28)=0.084 with a 95% confidence interval, assuming equal
variances. A t=0.084 is less than the critical value of 1.074, indicating that the results are not
statistically significant. The mean of intervention weights and the mean of baseline weights
could be caused by sampling variability.
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