Week 2

Hello, everyone


It seems to be a nightmare when I am required to confront with the math and statistics again due to they are not my cup of tea. However, a good attitude would motivate me to review them again.

First of all, to recall my memory, I need to look in a big picture to connect the idea of the statistics as the figure below. 

(https://sites.google.com/site/mystatistics01/chapter1/basic-theory)

In this week we are required to learn the four keywords consisting of measurements, errors, confidence, and probability. It is undeniable that measurements are used in everyday life and we are used to the unit of measurement or System International (SI). According to Steven’s theory, On the Theory of Scales of Measurement. These scales seem to measure the latent variables in social sciences such as attitudes, symptoms, personality, health literacy. The 4 scales of measurements are described in this theory. Personally, I called “NOIR” for the short form for helping me remember them.

Scales	Basic characteristics	Example
Nominal	A scale that measures data by name only. By the numbers given are not identified their values, but we use the numbers as a symbol of the things.	-          Nationality -          Gender -          Marital status -          Sex -          ethnic
Ordinal	A scale that measures by rank order only. we cannot measure the exact difference in numerical terms.	-          satisfactory of the services in AA hospital (excellent, fair, poor) -          order of birth-order of sibling -          level of education -          IQ levels -          Social class
Interval	Any scale that reflects only magnitude but does not contain equal intervals or an absolute zero	-          Attitudes -           Opinion -          Temperature
Ratio	Similar to an interval scale, a ratio scale includes a 0 measurement that signifies the point at which the characteristic being measured vanishes  (true zero).	-          No patients in the clinic -          Income -          Length -          weight

 


Have you ever experienced making repeated measurements of what the same physical quantity, but the results were not always the same answer?
     

          The answer is because of the “Errors”.

There are several types of errors influencing the accuracy of the measurements. Barford,1985, stated that several sources of errors including

1. Systemic errors

2. Random errors

3. Combinations of two random errors (number of significant figures)

4. Human errors

                                 Probability

Events can be assigned probabilities vary from 0 up to 1. For example,

Some events in life are certain…. Human will die someday (1)
But some events are impossible ….an elephant can fly (0)

It is said that probabilities close to 1 are quite likely to certain happening whereas probabilities close to 0 are almost impossible.
In my opinion, I would conclude that the measurement of apparatus allow we know the precision and the value of the experiment much as much possible, but there are some errors present as barriers to obtain the precision and the true values, the probability displayed the chance of inaccuracy of the measurements by setting the level of confidence to ensure the level of error.