1. Unit 5 Quiz: Review questions

2. Can you explain your answer?
Use your fingers to indicate your answer: 1=A, 2=B, 3=C, 4=D.
After viewing the question, show me your answer in 15 seconds.
Next, turn to your neighbor and you have one minute to convince him/her that you are right.

3. Even if the Pearson’s coefficient is very high, we still look at the data pattern in a scatterplot because:
there may be outliers in the data
the relationship between X and Y may be non-linear, but Pearson’s coefficient assumes a linear relationship
a and b
the data are sampled from two different populations.

4. Pearson’s correlation coefficient should be used for ________ data.
Nominal
Ordinal
Continuous

5. Spearman’s correlation coefficient should be used for ________ data.
Nominal
Ordinal
Continuous

6. How can we detect outliers in a scatterplot?
Cook’s distance
D-square
The eclipse covers the majority of the data. Any points outside the line are considered outliers.

7. What is confidence interval?
It is a way to estimate the exact point in the population.
It is a way to estimate the range of the population value.
It is a way to estimate the upper bound, the middle, and the lower bound of the population values.

8. Which of the following statements is false?
In correlation there is no distinction between DV and IV, or cause and effect
In correlation the Y variable is the outcome/effect and the X variable is the factor/cause.
Correlation coefficient ranges from -1 to 1.

9. Which of the following statements is true?
In a positive correlaton, as Y increases, X increases.
In a positive correlation, as Y decrases, X decreases.
In a negative correlation, as Y increases, X decreases.
All of the above are true.