Discussion
Which of the following statements are correct for Karl Pearson's correlation coefficient ?
(i) The scatter diagram of the data will give a straight line curve
(ii) The scatter diagram of the data will not give a straight line curve
(iii) Each of the variables is being affected by a large number of independent contributory causes of such a nature as to produce normal distribution
(iv) The forces so operating on each of the variable series are not independent of each other but are related in a causal fashion.
Answer: C
The correct statements are (i), (iii) and (iv).
These are the three assumptions of Karl Pearson's coefficient of correlation in the standard textbook account:
- Linear relationship: plotted on a scatter diagram, the paired values tend to lie along a straight line (i).
- Normality: each variable is affected by a large number of independent causes, so that it is normally distributed (iii).
- Cause and effect: the forces acting on the two series are related causally, not independent of each other (iv).
(ii) contradicts (i). Pearson's r measures only the strength of linear association; when the scatter diagram shows a curve, r can be close to zero even though the variables are strongly related. Every option containing (ii) is wrong.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development