Practice Quiz Week 2

# Practice Quiz Week 2 - Math 221 Statistics Practice Quiz...

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Math 221 - Statistics Practice Quiz Week 2 This quiz review covers materials from Weeks 1 and 2. Your quiz will be in Week 3 located in the Quiz Tab. Your quiz will mostly comprise of multiple choice, true/false, and essay questions. The answers are at the end of the questions. 1. The measurement that describes the variation of a data set is called the Standard Deviation . 2. When a scatter plot's (x,y) points are all pretty close to the "line of best fit", then how would you describe the relationship between the points? A strong linear relation exists between x and y. Feedback: A strong correlation exists when the plotted ordered pair points are close to the line of best fit. If the points line up exactly on the line of best fit, there is a perfect correlation. The correlation coefficient is a measure of the strength of the correlation. 3. True or False: Cause and effect relationships cannot be determined using the coefficient of determination. True Feedback: A primary characteristic of the correlation concept is that it only describes the fact that a linear relationship exists. The determination of cause and effect requires more study and analysis. That is not to say that a cause-and-effect relationship won't exist. It only says that it cannot be determined by the correlation. 4. True or False: Correlations are used to help identify the relationship between two variables. For example, the amount of rain in July (x) and the size of tomatoes in August (y) could be analyzed using correlation and regression techniques. True Feedback: Correlation and regression are the techniques statisticians use for analyzing relationships between variables. 5. The scores of the top ten finishers in a recent LPGA Valley of the Stars Tournament are listed below. (Source: Los Angeles Times) 73 67 72 67 76 72 73 68 71 73 Find the mode score. 73

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## This note was uploaded on 01/23/2011 for the course MATH 221 taught by Professor Calloway during the Spring '10 term at DeVry Arlington.

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Practice Quiz Week 2 - Math 221 Statistics Practice Quiz...

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