1. If the linear correlation coefficient of two variables is
zero, then there is no _______________ relationship between the
variables. A linear correlation coefficient of 0.92 suggests a
________________ linear relationship than a linear correlation
coefficient of -0.86. The value of the ___________________ always
lies between -1 and 1, inclusive. If the linear correlation
coefficient of the regression line is negative, then the
____________________ of the least squares (linear) regression line
must be negative. Give a detailed interpretation of the...
1. If there is no correlation between two variables, what is
the value of the correlation coefficient?
to. -1
b. 0
c. 1
d. -0
2. In a scatter diagram, on which axis is the dependent
variable always recorded?
to. x axis
b. y axis
3. What is the dependent and independent variable?
• time
• quantities produced
11. If “correlation does not imply causation,” what does it
imply?
12. What are some of the possible reasons for large correlations
between a pair of variables, X and Y?
17.What assumptions are required for a correlation to be a valid
description of the relation between X and Y?
If the sample correlation between two random variables is small
in magnitude (say 0.1), does that necessarily imply that the test
for the significance of the correlation will have a large p-value
(> 0.05)?
What is covariation between two variables?
How is "covariation" (or correlation) between two
variables different from "relationship" between them?
Why do we need regression analysis to establish
relationships between the dependent variable and one or more of the
independent variables and correlation analysis is not
enough?
Correlation and Causality: What is meant by the statement that
correlation does not imply causality? Part 2: Cause of Global
Warming: If we find that there is a linear correlation between the
concentration of carbon dioxide (CO2) in our atmosphere and the
global temperature, does that indicate the changes in the
concentration of carbon dioxide cause changes in the global
temperature? Why or why not? Part 3: Application of concepts:
Discuss and give at least one example of how you...
Each of the following scenarios describes a correlation
between two variables. State whether the correlation is most likely
due to a coincidence, a common underlying cause, or a direct cause.
If there is an underlying cause, state what you think it is. If you
believe that one variable directly causes the other, suggest
possible physical causation.
1. Sales of winter boots are positively correlated with
the sale of sidewalk salt.
2. I’ve noticed that the more hours I work each...
You wish to determine if there is a linear correlation between
the two variables at a significance level of α=0.10α=0.10. You have
the following bivariate data set.
x
y
85.9
65.4
73.2
49.4
62.2
36.9
86.4
52.3
76
52.8
70.8
34
77.6
59.4
70.1
47.2
80.2
65.8
83.9
46.2
80.1
47
68.8
50.8
85.5
82.9
74.3
69.9
72.7
42.8
87.1
65.6
70.4
59.3
85.2
64.5
63.3
31.9
92.6
80.4
87
62.2
77.3
63.8
93.9
64.4
What is the correlation coefficient...