Which of the following is a property of the linear correlation coefficient r?
Answer
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If all values of either the x or y variable are converted to a different scale, the value of r changes.
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The correlation r measures the strength of a linear and nonlinear relationship.
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The correlation r is not sensitive to outliers.
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The value of r is always between -1 and 1 inclusive.
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Use the given information to find the coefficient of determination.A regression equation is obtained for a collection of paired data. It is found that the total variation is 29.045, and the UNexplained variation is 13.833. Find the coefficient of determination.(Hint: You must first find the explained variation.)
Answer
Which of the following research hypotheses would be answered using a multiple regression?
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A) Is the mean weight of football players and baseball players significantly different?
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B) Is the mean weight of football players, baseball players, and soccer players significantly different?
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C) Is there a significant linear relationship between years of football experience and a player's salary?
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D) Is there a significant linear relationship between years of football experience, weight, college attended, and a player's salary?
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Answer
Which of the following research hypotheses would be answered using a multiple regression?
A) Correlation implies causality
B) The correlation r is a measure of the strength and direction (positive or negative) of two variables
C) If there is no linear correlation, a correlation does not exist.
D) Using mean scores to calculate the correlation is appropriate.
Which of the following describes the coefficient of determination?
Answer.
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The proportion of the variation in x that is explained by the linear relationship betweeen x and y.
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The proportion of the variation in y that is NOT explained by the linear relationship between x and y.
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The proportion of the variation in y that is explained by the linear relationship between x and y.
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The proportion of the variation in x that is NOT explained by the linear relationship betweeen x and y.
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Given the linear correlation coefficient r and the sample size n, determine the critical values of r. Use your finding to state whether or not the given r represents a significant linear correlation. Use a significance level of 0.05.r = -0.844, n = 5
Answer
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A)
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Critical values: r = +0.950, no significant linear correlation
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B)
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Critical values: r = +0.878, significant linear correlation
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C)
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Critical values: r = +0.878, no significant linear correlation
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D)
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Critical values: r = +0.950, significant linear relationship
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A set of data consists of the number of years that applicants for foreign service jobs have studied German and the grades they received on a proficiency test. The following regression equation is obtained: y = 31.6 + 10.9x, where x represents the number of years of study and y represents the grade on the test. What does the slope of the regression line represent in terms of a grade on the test?
Answer
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A) The grade on the test increases by an estimated 31.6 points for each additional year of study.
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B) The grade on the test increases by an estimated 10.9 points for each additional year of study.
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C) The grade on the test decreases by an estimated 31.6 points for each additional year of study.
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D) The grade on the test decreases by an estimated 10.9 points for each additional year of study.
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Find the value of the linear correlation coefficient r.The paired data below consist of the test scores of 6 randomly selected students and the number of hours they studied for the test.
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Hours
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5
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10
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4
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6
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10
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9
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Score
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64
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86
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69
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86
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59
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87
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Answer
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A)
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0.224
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B)
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-0.224
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C)
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-0.678
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D)
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0.678
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Use the given data to find the best predicted value of the response variable.Eight pairs of data yield r = 0.708 and the regression equation y = 55.8 + 2.79x. Also, mean y = 71.125. What is the best predicted value of y for x = 5.7?
Answer
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A)71.13
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B)71.70
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C)320.8
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D)57.80
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