# i need comentas

**A brief description of two statistical concepts that you think are most important to psychological research and explain why you think they are important.**

One statistical concept I believe is important to psychological research is reliability. Reliability is a measure that presents the outcome of the measurement free from error (Stangor, 2015). For example, if my dog gets weighed at the vet and she weighs 17.2 pounds, I take her off, and put her immediately back on, I expect her to still weight 17.2 pounds. Given that both times she weighed the 17.2 pounds, I would consider this form of measurement reliable. The test-retest concept of reliability refers to giving a test to the same group of people then giving the same test a week later (Stangor, 2015). For instance, if I gave my students an exam on a Tuesday and then give the same test the following Tuesday the students should receive the same score. This will make the test reliable. The limitation for test-retest is the influence the individual may have when given the test the second time (Stangor, 2015). For example, if I take a quiz online without getting my score back but found out a week later I was wrong on some of the questions, I most likely will change my choices the second time around which is known as the retesting effects (Stangor, 2015).

Another statistical concept I believe to be important to psychological research are measurement scales (Stangor, 2015). There are four specific measurement scales which include nominal, ordinal, interval, and ratio (Stangor, 2015). Norminal variables are also known as categorical variables because the variables have two or more categories without a specific order (StatSoft, 2008). Normal variables are categories that are named such as gender, race, and color (StatSoft, 2008). Ordinal variables provide a ranking order, for example lowest to highest which allows us to see which has less or more; but, not by how much (StatSoft, 2008). For example, if we use undergraduate studentsâ€™ educational mentality and order them from lowest (freshman) to highest (senior), it is a possibility there would be a difference between lower classman and upper classman. However, we do not know by how much. Interval variables allows researchers to rank the order of the items that are being measured in addition to measure and associate differences in size (StatSoft, 2008). Weather temperature would be an example of an interval variable. Last, ratio variables, which are similar to interval variables but identifies as an absolute zero point which then indicates you can use a variable such as distance as the ratio of measurements (StatSoft, 2008).

**Briefly describe two different statistical concepts that you find most interesting and explain why you find them interesting.**

One statistical concept I find interesting are self-reports which are questions participants answer by the interviewer or a questionnaire (Stanger, 2015). Free-format self-report measures allows participants to share their thoughts or feelings about a topic without any pressure (Stanger, 2015). On the other hand, fixed-format self-report measures gives the participant choices and he or she chooses what best describes them. An example of a fixed-format self-report is the Likert scale (Stanger, 2015). An example of a Likert scale are the surveys we get after our quarter is complete about the class we attended. Although this is an interesting form of statistical concept, the answers may not always be accurate because the person answering may put answer down based on what he or she thinks the researcher wants to see rather than how she or he really feels (Stanger, 2015).

The second statistical concept I find interesting are behavioral measures (Stanger, 2015). Some behavioral measures include measures such as frequency, duration, intensity, latency, and speed (Stanger, 2015). This concept is interesting because after all, psychology is the study of human behavior. Some examples of conceptual variables which could be used for behavioral measures are personality style, aggression, desire for uniqueness, honesty, dieting, environmental behavior, and prejudice (Stanger, 2015). An example of personality style may be the way a person dresses and presents his or herself. One way a child whose aggression could be measured is by how the child reacts when he is constantly being picked on.

**Briefly describe, as best you can, two statistical concepts that are most difficult for you to understand and explain your difficulty in understanding them.**

One statistical concept I find difficult to understand is validity. I have always had a difficult understanding validity. I believe it is because I think too hard about it. I know validity are tests that measure what the researcher is set out to measure (Stanger, 2015), but I still find it confusing. There are also several other forms of validity such as construct validity, face validity, convergent validity, discriminant validity, criterion validity, predictive validity, and concurrent validity (Stanger, 2015). I understand validity if it presented to me in a simplistic way. For example, a thermometer is supposed to measure temperature and personality test such as the MMPI-2 is supposed to measure an individualâ€™s personality. The only time I seem to have difficulties understanding, most likely overthinking, is when validity is presented in a textbook or classroom setting.

Another statistical concept I find difficult to understand is calculating descriptive statistics. All of the studies I participated in or the one I published, we used similar tools such as surveys. With surveys, the research can calculate percentage of the total amount of participants. According to Table B.1 provided by Stanger (2015) I studied the calculation of descriptive statistics provided and added everything up. I did come up with the solutions indicated. According to Stanger (2015) the symbol ( indicates the number of scores that ought to be summed. However, it starts getting complicated when the summation notation is included = 23 (Stanger, 2015). I believe I would find this statistical concept difficult until I get used to the terms again and symbols used to formulate the results in a research study. Right now, I do think it is outside my comfort box but, I am determined to refresh what I know I have been taught in the past.

References

Stangor, C. (2015). *Research methods for the behavioral sciences* (5th ed.). Stamford, CT:

Cengage Learning.

StatSoft. (2008). *Elementary concepts in statistics*. Retrieved

from http://www.statsoft.com/textbook/elementary-concepts-in-statistics/

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