Introduction to Correlation

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Show your work for each problem.

1.
When both variables increase together, this is called:
1. a)Causation
2. b)Positive correlation
3. c)Negative correlation
4. d)No correlation
2.
The correlation coefficient always falls between which values?
1. a) and
2. b) and
3. c) and
4. d) and
3.
If the correlation coefficient is , what type of correlation exists? (Answer: positive, negative, or none)
4.
As the price of a used car decreases with age, this represents:
1. a)No correlation
2. b)Negative correlation
3. c)Perfect correlation
4. d)Positive correlation
5.
A correlation of indicates what type of correlation? (Answer: positive or negative)
6.
Which correlation coefficient represents the STRONGEST relationship?
1. a)
2. b)
3. c)
4. d)
7.
Classify the correlation by its direction and strength.
8.
A study finds . Is this correlation weak, moderate, or strong?
9.
Ice cream sales and drowning incidents both increase in summer. This is an example of:
1. a)Correlation without causation
2. b)Negative correlation
3. c)No correlation
4. d)Causation
10.
A researcher finds that as study time increases, test anxiety decreases. Describe this correlation.
11.
A scatter plot shows points going upward from left to right. The calculated correlation is . Interpret this fully.
12.
Which statement correctly describes the relationship between correlation and causation?
1. a)Correlation always implies causation
2. b)Correlation and causation are the same thing
3. c)Correlation can exist without causation
4. d)Causation cannot exist with correlation
13.
Research shows that countries with more Nobel Prize winners also have higher chocolate consumption. The correlation is . Does chocolate make people smarter? (Answer: yes or no)
14.
Order these correlations from weakest to strongest relationship: , , ,
15.
A study finds that students who eat breakfast score 10% higher on tests. The correlation is . What can we conclude?
1. a)Students should skip breakfast to focus on studying
2. b)Eating breakfast causes higher test scores
3. c)There is a moderate positive correlation between breakfast and scores
4. d)There is no relationship between breakfast and test scores