Research Methods questions

Please answer these 4 questions below. not less than 90 words, no plagiarism, cite the sources, apa style 

1)Why do we have to be concerned with ethics when conducting a research study?

2) What are the scales of measurement in Research Methods? Explain each briefly?

3) Compute measures of central tendency below:

a)Mean, median, and mode for the grades taken by students

b)Mean, median, and mode for the number of hours studied

4) Does the number of hours studied correlate with the grades taken? Please provide a narrative explaining the relationship between the number of hours studied and the grades by running correlation analysis in Excel. 

(In Excel, use insert function to compute the measures of central tendency and use the CORREL function to find the correlation coefficient between between the number of hours studied and the grades. The value you will get will represent to what extent these two variables are correlated. For example if the result is 95, it means that these two variables are almost perfectly correlated (95%).