Once the variables of the study are identified, the researcher starts observing the presence of them in their subjects. This process involves ascribing numerical values to the observations made, called Measurement. Measurements provides quantitative data pertaining to the observations made on the variables.
Later, application of various statistical techniques and methods allow the acquisition of vital information on the characteristics of the variables studied. Information or data pertaining to the variables can be either qualitative or quantitative by nature. Depending on this nature of the data measured, we have different scales of measurement.
Scales of Measurement:
There are four types of scales of measurement. For qualitative data, there are nominal and ordinal scales. For quantitative data, we have interval and ratio scales.
The nominal scales measure variables which can take any one of the two possible qualitative values. Example: Gender. It can be either male or female. That is why, any two values, say 1 and 2 can be assigned for male and female genders respectively.
The ordinal scales measure variables whose values are categorized in a qualitative order. For example, under the grading system of evaluation, students acquiring marks between 85 - 100 are awarded "O" grade. Similarly, students with marks in the range 70 - 85 percentage are awarded "A" grade.
The interval scales have certain degree of difference between their previous and successive readings. These scales have no arbitrary zero point of reference. For example, the scale in a thermometer is an interval scale. When it reads 80 degrees Celsius, it does not mean that it is now twice hotter than 40 degree Celsius temperature. Also, if the I.Q. of one student is 90 and the other is 135, it does not mean that the latter has 50 % more intelligence than the former.
The ratio scales involve values in a scale which are certain times a fixed unit. These scales have an arbitrary zero reference point and the rest of the readings in the scale are in certain ratio to the fixed unit. For example, when we say that a rice bag weighs 2kgs, it means that physically, the bag is 2 times heavier than a 1 kg standard weight which is the fixed unit here. Similarly, a 60 kgs boy is always twice heavier than a 30 kgs boy.
Conclusion: Most of the times, the research studies in education deal with nominal qualitative scales and interval quantitative scales.
Later, application of various statistical techniques and methods allow the acquisition of vital information on the characteristics of the variables studied. Information or data pertaining to the variables can be either qualitative or quantitative by nature. Depending on this nature of the data measured, we have different scales of measurement.
Scales of Measurement:
There are four types of scales of measurement. For qualitative data, there are nominal and ordinal scales. For quantitative data, we have interval and ratio scales.
The nominal scales measure variables which can take any one of the two possible qualitative values. Example: Gender. It can be either male or female. That is why, any two values, say 1 and 2 can be assigned for male and female genders respectively.
The ordinal scales measure variables whose values are categorized in a qualitative order. For example, under the grading system of evaluation, students acquiring marks between 85 - 100 are awarded "O" grade. Similarly, students with marks in the range 70 - 85 percentage are awarded "A" grade.
The interval scales have certain degree of difference between their previous and successive readings. These scales have no arbitrary zero point of reference. For example, the scale in a thermometer is an interval scale. When it reads 80 degrees Celsius, it does not mean that it is now twice hotter than 40 degree Celsius temperature. Also, if the I.Q. of one student is 90 and the other is 135, it does not mean that the latter has 50 % more intelligence than the former.
The ratio scales involve values in a scale which are certain times a fixed unit. These scales have an arbitrary zero reference point and the rest of the readings in the scale are in certain ratio to the fixed unit. For example, when we say that a rice bag weighs 2kgs, it means that physically, the bag is 2 times heavier than a 1 kg standard weight which is the fixed unit here. Similarly, a 60 kgs boy is always twice heavier than a 30 kgs boy.
Conclusion: Most of the times, the research studies in education deal with nominal qualitative scales and interval quantitative scales.
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