The Statistical Analysis Homework required students to read a specific article and offer their insights on various aspects related to the statistical test used in the research. The questions posed in the homework included assessing the appropriateness of the statistical test, discussing what the article added to their understanding, identifying strengths and weaknesses in the research, and suggesting a procedure for redesigning the analysis.
- Yes, the statistical test used in the article which was the Independent sample t-test was appropriate. An Independent sample t-test can be conducted between the control group and experiment group, and a paired sample t-test can be conducted within the group.
- Differences between the two conditions can be caused in only two ways in an independent-measures design which was used in this study as the pretest/posttest statistical analysis: by differences in what we did to the subjects, or by subjects in one group behaving differently than people in the other group (because they are different people with different abilities, motivation, arousal, and so on). The variations between individuals may cause significant random variation in performance within each group, as well as between the two groups.
- Strength of the Research Method/Analysis
- Before the research starts, the pretest may determine whether there are any significant differences between the experimental and control groups. The experimental group is then given the therapy, and both the experimental group and the control group are given a posttest at the conclusion.
- Another benefit of the pretest-posttest design is that the researcher may establish not only whether there is a difference between the experimental and control groups, but also how much of a change or growth occurred between the pretest and the posttest.
- This kind of design is popular in education because we often want to know not only if there is a difference between groups, but also how much of a change or growth happened between the pretest and the posttest.
- Before the independent variable is added, random homework is the best technique for establishing the initial equality of comparison groups. As a result, random homework is intended to remove any possible confounds. The method, however, does not ensure group equality and random error owing to individual variations is still to be anticipated.
- The variability of scores in a two-group study is made up of both within-group and between-group variability. Extraneous factors are the cause of variation within groupings. Confounding factors combined with the impact of the independent variable cause group variation.
- The main drawback of a pretest-posttest control group design over a posttest-only design is that internal validity may be jeopardized due to the testing danger.
- Another danger may arise if the pretest and the treatment interact in some way. If the intervention is aimed at improving academic performance, this danger may not be as severe.
- An independent samples t-test or one-way independent samples analysis of variance may be used to evaluate a two-group independent samples design (ANOVA). When there are two or more groups, t-tests are suitable, whereas ANOVAs are appropriate when there are two or more groups.
- ANOVA should be used to evaluate an independent sample design with more than two groups. A priori planned comparisons or post hoc comparisons may be used to identify where differences may exist between particular groups. This may be hard to determine using the independent-sample t-test.
- Way to redesign the study
- In a one-group posttest design, the dependent variable is assessed twice: once before and after the treatment is applied.
- The design is similar to that of a within-subjects experiment, in which each participant is evaluated first in the control condition, and then in the treatment condition.
- It differs from a within-subjects experiment in that the sequence of conditions is not counterbalanced since a participant cannot be examined in the treatment condition first and then in the “untreated” control condition.
Weakness of the Research Method/Analysis
A One-way post-test design Only can be used to redesign this study. In such a design, treatment is applied (or an independent variable is changed) and then a dependent variable is assessed once after the treatment is administered in a one-group post-test-only design. Before we get into the analysis of this design, it is important to grasp what the word "different" means in the context of "Is there a difference between the groups?" A "bell-shaped" curve that represents the group's distribution on a single variable may be used to represent each group.