Questions
Questions
- The population is set of all measurements of the focus while the sample is a subset of the population. It is vital for a researcher to study the sample in order to detect a statistically vital outcome. Sampling error is an error which is obtained from samples when estimating the population size.
- Descriptive statistics deal with procedure used to summarize the information in the set of measurement. For example, collection and summarization. Inferential statistics use procedures to make predictions of a population. For example, hypothesis testing. The researcher uses them to establish relationships between variables.
- The independent variable is one that can be manipulated in an experiment. The dependent variable is one that depend on the independent variable. Confounding variable is one that has an unplanned effect on the dependent variable. For instance, in the research to test the hypothesis if there is an association between children’s benefit in social studies achievement and their self-concepts. The self-concept is an independent variable and social studies achievement is a dependent variable. Intelligence might affect the social studies achievement, but since it is not related to the focus of study it is referred to as confounding variable.
- Nominal is the scale in which objects or people are assigned to categories that have no numerical properties. The ordinal is the scale in which objects or people are categorized, and the categories create a rank order along a continuum. The data measured with this scale have an identity and magnitude, but lack unit size and absolute zero. An interval is the scale in which the units of measurement between the numbers are all equal in size (Jackson, 2012). The ratio is the scale which has absolute value and zero indicates a lack of the variable being measured.
Measures of Central Tendency
- The purpose of measuring the central tendency is to determine the middle value within a data set. Mean is the summation of all values in distribution divided by value of numbers.. The median is a midpoint of the data in ascending order. The mode is the most common number.
- The median is used to show the middle number in ascending order. The mean is used to calculate the average of given values, while the mode is used to calculate the most occurring numbers.
- The diagrams below show the normal, positive and negative screwed distributions.
Source: http://education-portal.com/academy/lesson/skewed--examples-definition- quiz.html#lesson
- The example where a mean age of 15 is obtained when all but one of the values is less than 5 shows how much mean can be affected by extreme scores. This is the reason why the median is used in cases where the data is skewed.
Variability
- The purpose of measuring variability is to offer a quantitative measure of the difference between the scores in the distribution. The range is the subtraction of the smallest value of the largest. Variance is used to measure the variation of numbers in the distribution. Standard deviation is used to show the dispersion from the mean. The range is considered a crude measure of variability because significantly affected by extreme values.
- Deviation score is the difference between any one score and the mean. The sum of squares is the addition of squared deviations from the mean. Neither of these can be negative because the scores must show variability.
- When the standard deviation is zero, it means there is no deviation.. This show all values in the distribution must be equal to the mean values in the distribution.
- A score transformation is used to refer to the constant that changes score in a distribution to one on a different scale. Therefore, when some constant amount is added to each score in a distribution, the standard deviation remains unchanged. This is so because each score changes by the same amount so that the spread of scores remains unchanged. Similarly, when each score is multiplied by a constant, the standard deviation of the new score is the constant number times the old standard deviation (Myers, Well and Lorch, 2010). Therefore, the standard deviation of the transformed distribution is changed by multiplications.
Hypothesis
- We test the null hypothesis because it is usually regarded to be true. It can be rejected or accepted. The alternative is a residual of null hypothesis.
- The estimation is very significant in research because it used to determine the size of the sample. Hypothesis testing generalizes where there are more than two groups, whereas estimation is not intuitive when there are more than two groups. It is reasonable to use estimation after hypothesis test because the estimation is usually unbiased and consistent with the sample.
- The type 1 error occurs when the null hypothesis is rejected when it is true while type 2 error occurs when the null hypothesis is not rejected when the alternate hypothesis is true.
- The level of significance is the probability of rejecting the null hypothesis when is usually true. The advantage of using significant level 0.01 over 0.05 is that there is less probability of getting the type 1 error. Smaller level is also vital when using large sample sizes.
- The advantage of using the level of significance is that it reduces the chance of the result being manipulated by the analyst when it does not meet his or her expectation.
The purpose and process of educational research
- The educational research helps to understand the current state regarding the idea of the research. It helps to establish if the research problem has been covered and whether revision is required.
- The major component required in conducting educational research is planned, review the research, establish the purpose of research, consider the research implications and constructing the research and gathering the data. These components are connected in that the failure of one step can lead to failure of the other component and the entire process.
- When beginning the literature review is vital to use secondary sources because they provide published information about the problem in the research.
Miscellaneous J
- I can stay current in my study by attending conferences and taking advantage of networking opportunities.
- I can consider joining the research institutions, organizations that deals with publication and data analysis.
- I have read the educational research journals that have helped me to analysis the research problem effectively.
References
Education Portal (2012). Skewed Distribution: Examples, Definition & Quiz | Education Portal. Retrieved February 10, 2014, from http://education-portal.com/academy/lesson/skewed- -examples-definition-quiz.html#lesson
Jackson, S. L. (2012). Research methods and statistics: A critical thinking approach. Belmont, CA: Wadsworth Cengage Learning.
Myers, J. L., Well, A., & Lorch, R. F. (2010). Research design and statistical analysis. New York: Routledge.
