Stat 160 Prequiz over Section 1.10

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1. Which of the following is a measure of the relationship between two variables?

The sample interquartile range.
The Hodges-Lehmann estimate.
The sample range.
The sample correlation coefficient.
2. Which of the following is not true about the correlation coefficient?

It measures the linear relationship between two variables.
It is computed using the sample covariance and the standard deviations of the two variables.

It always takes values between -1 and 1.
It has the value 1 if there is a perfect circular relationship between the two variables.
3. Suppose we fit the linear model Y = a + bX + e using the least squares technique. What does R2 = .80 mean?

We have accounted for 80% of the variation in Y.
We have accounted for 20% of the variation in Y.
The value of the slope parameter is .80.
It has no practical meaning.
4. What is one advantage of using RW2 (which corresponds to the Wilcoxon fit) instead of R2?

RW2 is simpler to compute as compared to R2.
RW2 is always greater than R2.
RW2 is always less than R2.
RW2 is less sensitive to outliers than R2.