ESSENTIALS OF STATISTICS
Through the centuries, man has been interested in determining the number of birth rate, mortality rate, occurrence of certain events at certain periods of time, crop yield and the frequency of failures in school entrance test among many others. In these activities, he deals with the counts or numeral measures of activities, events and things, which are called statistics in a limited sense.
In counting activities, events, and things the measurement that are collected from the original information are called raw data. These data may be treated by statistical methods that are used to describe, to relate or associate, and to make inferences. In the method of description, the measure to apply is known as descriptive statistics. In the method to relate or associate two variables, correlational statistics is employed. And in making generalizations about the population
In the method of description, the measure to apply is known as descriptive statistics.
In the method to relate or associate two variables, correlational statistics is employed.
And in making generalizations about the population from which our sample has been drawn, the measure to use is inferential statistics.
Statistics as defined scientifically
From the research point of view, statistics is a science which deals with methods in collection, gathering, presentation, analysis, and interpretation of data. Data gathering involves getting information through interviews, questionnaires, objective observations, experimentations, psychological tests and other methods.
Usually the information is translated into numerical or quantitative data. By using graphs, figures, and tables the data collected can be exhibited. This becomes part of data presentation. Data presentations in tabular form are of two types, the text or summary table which is found in the body of the research work, and the reference table which is usually found in appendices.
If your interest is on the few members of the population to represent their characteristics or traits, these members constitute a sample. The measures of the population are called parameters, while those of the sample are called estimates or statistics.
Use of Statistics
Statistics is a branch of mathematics that can be used for many purposes. Some of these are briefly described below.
1.It can give a precise description of data. This is a function of statistics which enables us to make accurate statements or judgments about averages, variability, and relationship. An example of this purpose is when you describe the academic performance of a group of pupils according to the computed mean, standard deviation, and correlation with another factor.
2. It can predict the behavior of individuals. In school, the grades of students can be predicted through a scholastic aptitude test. In industry, the work performance is usually predicted by an aptitude test related to that particular type of work. A teacher’s performance may also be predicted by his performance in an instrument like a teacher aptitude test. Of course other sets of data or psychological tests can be used to predict the success of a teacher in his work. To measure the success of a pupil, teacher, or a worker, we may have to compute measures like the mean, standard scores, percentiles, stanines and other statistical methods.
3. It can be used to test a hypothesis. We can determine whether a variable is related or not to another variable through a test of inference such as in correlation. Other statistical measures we can apply for inferential purposes are the t-test, chi-square test, F-test, and others. It is wise to remember that your choice of the statistics to use in testing hypothesis depends upon the nature of your data. This includes the scale of measurement used such as nominal, ordinal, interval, and ratio; and its distribution whether normally distributed or not; and other considerations such as your purpose.