internal and external validity

Internal and External Validity.
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Question 1
One threat to the statistical conclusion validity would be the random heterogeneity of respondents. The type of people that are sampled in any study causes this. The main reason is that they make it harder to see the relationship between two variables. If the group of respondents is colossal as was the case in the study that was conducted by Burgette and Jackson they are likely to vary the measures and observations. Although in most cases this variety is always related to the phenomena that are being studied, part of it is more likely to comprise of the individual differences that do not relate to the variables that are under investigation. It is a plausible threat because the researchers stated the number of the participants and put the figure at 1382 CITATION Bur09 l 1033 (Burgette & Magun-Jackson, 2009).
Question 2
The researchers sought to find out the effect of a freshman orientation course on the persistence of students at a college. For any study that is conducted, there is always a risk of the test subjects or respondents dropping out of the test. Either the black or white students could have dropped out for a variety of reasons. Furthermore, such a threat, although not mentioned by the researcher, might occur at any point during the study. Such a threat is referred to as attrition and is likely to affect the internal validity of the survey.
Question 3
Before conducting the test, the researchers had formulated their hypothesis.

It was a well-established fact obtained from previous studies and conducted researches that the orientation course had no effect on students beyond the second year. In this research, there was a hypothesis that those who took the freshman orientation course tended to do better than those who did not. The creation of such a theory presents a threat to construct validity in the form of experimenter expectancy. It may make the researcher to bias the results of the study in a myriad of ways that may be both conscious or subconsciously. There is also a risk of communicating information that he or she believes to be true. For instance, any student who does well and did not undertake the freshman course may be taken to have cheated or passed in an illegal manner. To avoid such a scenario is by not having any prior expectations or theories He might communicate what the desired outcome ought to be and in doing so becomes prejudiced. It is a possible threat because the chances are that the researcher had his set of opinions even before conducting the experiment. He had hypothesized several things and this may bias the results of the study.
Question 4
External validity is mainly related to generalizing. For this reason, one threat to external validity that may exist is the interaction of casual relationship with outcomes. This occurs when the same results cannot be expected when a researcher uses a different operation or measure of the outcome or dependent variable as this will lead to different results. The study conducted by the researchers looked at the relationship between the importance of taking the introductory class and completing a degree. It is a plausible threat because the results provided by the researchers show that it took a different number of years for students to graduate depending on which year they enrolled in a university. Although there was a consensus that graduation took longer than four years, there were those who took five years to graduate while others took up to six years to attain a bachelor’s degree.
Question 5.
Perhaps the easiest threat to control was that which was posed to construct validity. As stated, the experimenter expectancy arises when researchers have certain expectations of a study. In the study conducted by Magun-Jackson and Burgette, one clear way of controlling the threat was by not having any expectations. This would make the results free from any bias or prejudice.
References
BIBLIOGRAPHY Burgette, J., & Magun-Jackson, s. (2009). Freshman Orientation, Persistence, and Achievement: A Longitudinal Analysis. J. College Student Retention, 235-263.