Measurement in this case refers to use and application of rules for assigning numbers to different objects. Different measurement scales are applied for different classes of objects. For instance, measuring a height of a sample population may be done in inches, whereas the weight of the sample population may be done in kilograms. The scale measurement constitutes three important properties. According to Kaplan and Saccuzzo (27), these are magnitude, absolute zero, and equal intervals. Magnitude refers to the ability to represent more, less or equal attributes of a given entity or object. This is clearly shown in a scale of weight where one individual has more weight compared to another. Absolute zero is a property where nothing of an object being measured exists. An equal interval refers to cases where the difference between two points on a scale has the same meaning as the difference in scale for other two points on the same scale. This can be illustrated in a weighing scale where the difference in weight between 8kg and 11kg is same as the difference in weight between 15kg and 18 kg.
According to Kaplan and Saccuzzo (29), the four main types of scales used are the nominal scale, ordinal scale, interval scale and the ratio scale. Nominal scales are used to name objects, therefore, perform a qualitative role. The nominal scale does not have any of the three properties of scales of measurement. The ordinal scale has only the property of magnitude, which allows for ranking of objects without providing any meaning to differences in ranks. The interval scale has the property of magnitude and the property of equal intervals. An example of such a scale is the temperature Fahrenheit scale, which does not have the property of an absolute zero. A ratio scale is a scale, which has all the three properties of scales of measurement.
Descriptive Research Design
Gravetter and Rorzano (364) discuss descriptive research design to involve the measurement of a variable as they exist naturally. A point to note here is that descriptive research design does not take into account any relationships that may exist between any of the variables being researched. Descriptive research designs types include observational research, case study research and survey research. Case studies involve the description of a single individual in detail; survey research design involves the description of people’s responses regarding attitudes and behavior while observational research design involves a description of behaviors as they occur naturally. Case studies are mostly applied in clinical psychology.
APA Paper Research
APA paper research involves preparation of papers based on guidelines that are written in the Manual published by the American Psychological Association. These guidelines have been reviewed several times. The use of APA formatting style for research papers is not limited to psychology only but also extends to other fields such as sociology, nursing, and education. An APA paper research normally consists of seven sections. The first section is the title page that consists of the title of the paper, names of authors and affiliations of authors. The second section is the abstract that provides a brief summary of the entire paper and contains between 150 and 250 words. The third section is the introduction, which provides a background and reason of the study using previous literature on the study. The fourth section is the method section that describes how the study was conducted, the participants involved, material used, and the activities of researchers and participants. The fifth section is the results section that provides detailed results and statistics of the study. The sixth section is the discussion section that provides an understanding and interpretation of the results. The seven and final section is the reference section that provides location of the work cited in the paper.
The abstract is located on the second page of the APA research paper. The abstract provides a short summary of the whole paper and contains between 150 and 250 words. In addition, the abstract also provides information relating to the major segments of the paper such as the introduction, method, results and discussion. The abstract should not contain detailed information regarding the four major sections outlined earlier in this paragraph. The tile abstract is normally centered.
According Chow (8), research methodology used by psychologists can include non-experimental investigations, experimental investigations, and quasi-experimental investigations. A non-experimental investigation involves an empirical study that does not have any form of control. Experimental methodology involves a form of theoretical control and a quasi-experiment involves a situation where one of the controls may not be used. The choice of the research methodology to use will depend on the data analysis procedures that the psychologists will use before commencing the research. In the use of non-experimental investigations, the researcher has to decide the research plan, and the measuring instrument to use. In quasi-experimentation investigations, the researcher needs to select the appropriate design and the outcome measure. Experimentation investigations will require the researcher to have a suitable experimental design, experimental task, and a dependent variable before commencing data collection.
Frequency Distribution and Graphs
A frequency distribution graph represents a picture of the data that has been brought together on a frequency distribution table. The graph of a frequency distribution represents a two-dimensional illustration of how frequently certain events occur. These graphs are used to analyze the different data that are collected by the researchers. Graphs that are used vary and may include histograms and polygons. The polygon is a form of a line graph where the data is represented in the form of points on a line, whereas the histogram is a graph where the data is represented in the form of vertical bars. From the frequency distribution graphs, measures of central tendencies can be obtained. This includes the median, the mean, and the mode. The mean represents the average of the data represented in the frequency distribution table; the median represents the midpoint of the frequency distribution.
Measures of Central Tendency
The measures of central tendency involve statistics that are used to analyze the center of distribution of data. The measures of central tendency include mean, median, and mode. The mean is the most frequent measure of central tendency that is used and is used to represent the average value of the data collected. The mean is calculated by dividing the total sum of the scores by the amount of the scores. The advantage of using the mean is that using a sample mean provides a better estimate of the population mean than the mode and the median. The median score represents the 50th percentile of the scores. The median just like the mode has the benefit of not being affected by extreme scores. The mode represents the most frequently used score.
Measures of Variability
Measures of variability are used to establish the extent of spread of scores from the average scores. The measures of central tendency provide a sufficient base for the linking of two or more sets of frequency distributions. The most frequently used measures of variability include the standard deviation and the range. Other measures of variability include the quartile and the average deviation. The range is the variation between the uppermost and the lowest score. The range is highly influenced by extreme scores. The standard deviation is the square root of the average squares of the deviations of each score from the mean. The standard of deviation is more reliable as a measure of variability since it incorporates the mean in its computation.
The Z-score and Normal Distribution
Normal distribution is a scenario in a histogram or a line graph where majority of the scores are represented in the middle of the distribution. The normal distribution curve provides a description of the distributions of sets of data. This implies that the distance between the scores and the mean can be determined. The Z score is used to determine the standard deviations of a different data points from the mean. If the scores are below the mean, the scores have a negative Z score whereas scores above the mean have a positive Z score.
Chow, Siu. L. “Methods in Psychological Research”. Methods in Psychological Research, In
Encyclopedia of Life Support Systems (EOLSS), Eolss Publishers, Oxford, UK. 2002. PDF file.
Gravetter, Frederick J., and Lori Forzano.Research methods for the behavioral sciences. 4th Ed.
Belmont, CA: Wadsworth Cengage Learning, 2012. Print.
Kaplan, Robert M., and Dennis P. Saccuzzo. Psychological testing: principles, applications, &
Issues. 8th ed. Belmont, CA: Wadsworth, Cengage Learning, 2013. Print.