Question

If you were using the Fourier Series coefficient c_k to determine if an anomalous signal is present, what characteristics (amplitude, frequency, time-shift) make it easier to detect?

In other words, is it easier to detect an anomalous signal that is large in amplitude, but at the same frequency and zero time shift? Or is it easier to detect an anomalous signal that is small in amplitude and at a different frequency? Or…

Which coefficient would you use? Or would you use multiple coefficients?

Provide a brief discussion of your answers, and justify them with appropriate calculations and/or plots. Note: Recall that the coefficient c_k can be defined as c_k=|2∙d_k |

Answer 1

1.

Market research can be categorized into two major categories namely primary and secondary research.

Primary research is the one which provides direct feedback/opinion of the population that needs to be analyzed. It is the research which undergoes first-hand data. This is because the reliability and validity of primary data is more which makes the conclusions more accurate. However, the reliability and validity are subject to the research ethics being followed properly.

The examples of primary data collection methods are:

Survey

Personal interview

Observations

Secondary research is the one which is not based on primary data. It is the data that is taken from various sources such as company’s website, newspapers, and other sources. The reliability of this data is subjected to the accuracy of the source from where it is taken.

Some examples of secondary sources are:

Already existing research works

Magazines

Newspapers

Websites