Correlation - Online Test
Q1. If all the plotted points form a straight line from lower left hand corner to the upper right hand corner then there is
Answer : Option B
Explaination / Solution:
A line from lower left hand corner to the upper right hand corner indicates perfect positive correlation with the value of r equal to 1.
Q2. If the plotted points in the plane form a band and they show a rising trend from the lower left hand corner to the upper right hand corner, then there is
Answer : Option A
Explaination / Solution:
A band showing a rising trend from left to right indicates a close positive relationship and thus there is high positive correlation.
Q3. Examples of negative correlation are
Answer : Option A
Explaination / Solution:
Negative correlation is said to exist when a rise in the value of one variable leads to a fall in the value of the other variable and vice versa.
Q4. If the plotted points in the plane are spread all over the diagram, then there is
Answer : Option C
Explaination / Solution:
Data points scattered all over the diagram indicate no association between the two variables and hence there is no correlation.
Q5. Study of price and demand eliminating supply side
Answer : Option B
Explaination / Solution:
Partial correlation measures the degree of association between two random variables while controlling or eliminating the effect of one or more other variables.
Q6. Rearrange the following steps
a. Find the mean of two series x and y
b. Take deviation of the two series from their means.
c. Square the deviations and get the total
d. Multiply the deviations of x and y and get the total.
e. Substitute the values in the formula.
Options are as follows
a. Find the mean of two series x and y
b. Take deviation of the two series from their means.
c. Square the deviations and get the total
d. Multiply the deviations of x and y and get the total.
e. Substitute the values in the formula.
Options are as follows
Answer : Option B
Explaination / Solution:
This is the correct sequence to calculate Karl Pearson's correlation coefficient. It will take a value ranging from -1 to +1. Positive values of correlation coefficient indicate positive relationship between the two variables, while negative values are indicative of a negative relationship. Zero value implies no relationship.
Q7. Following are the examples of positive correlation except
Answer : Option D
Explaination / Solution:
It is an example of negative correlation because with the rise in temperature the sale of woollen garments will fall.
Q8. Degree of Correlation Between + 0.25 and + 0.75 is
Answer : Option B
Explaination / Solution:
If value of r is close to 0, correlation is said to be low, while the values of r close to ±1 represent high correlation. Degree of correlation between +0.25 and +0.75 will therefore be moderate.
Q9. The diagrammatic representation of two variables is called _________
Answer : Option A
Explaination / Solution:
A scatter diagram is a graph in which the values of two variables are plotted along the 2 axis.
Q10. The relationship between three or more variables is studied with the help of _________ correlation
Answer : Option D
Explaination / Solution:
Multiple correlation is used when the relationship between more than two variables is under study.
