Take a Test - Danny OrtegaxCorrelation and regression a https://www.mathxl.c Mos

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Take a Test - Danny OrtegaxCorrelation and regression a https://www.mathxl.c Most Visited-e Getting Started Marg in of Error Ca culatorC Search Textoook SolutionsG screenshot mac- Google se+ Test.aspx?testid-163985146 C Search Mat 150 Intro to Statistics Fully Online Summer Il Section 0502 Danny Ortega 8/15/17 11:45 AM Test:Final Exam Time Remalning: 03:28:49 Submit Test This Question: 1 pt 11 of 30 (5 complete) This Test: 30 pts possible The eruption height and the time interval after eruption of a geyser were measured and are shown below. Answer parts a-c. 150 83 120 145 84 127 78 124 67 138 80 123 73 107 62 Interval after (y) ick here to view a table of critical values a. Find the value of the linear correlation ccefficientr Round to three decimal places as needed.) b. Find the critical values of r from the table showing the critical values for the Pearson correlation coefficient using =0.05 The critical values are ± (Round to three decimal places as needed.) c. Is there sufficient evidence to conclude that there is a linear correlation between the two variables? O A. No, because the absolute value of the correlation coefficient is greater than the cnitical value Yes, because the absolute value of the correlation coefficient is less than the critical value Yes, because the absolute value of the correlation coefficient is greater than the critical value No, because the absolute value of the correlation coefficient is less than the critical value B. C. D. Click to select your answer(s).

Explanation / Answer

a)
Number of cases 8
X = 1034
Y = 593
X^2 = 135,052
Y^2 = 44447
XY =77417
X Y = 613,162

r = ( XY - X Y / n ) / SQRT { [ X^2 - (X)^2 / n] [ Y^2 - (Y)^2 / n]}
Numerator of r = (77417) - 613,162 / 8 = 771.55
Denominator of r = SQRT[135052 - (1034)^2 / 8] * SQRT[44447- (593)^2 / 8]
= SQRT[1407.5] * SQRT[490.875]
r =771.55 / [37.51] * [22.16]
Correlation coefficient r =0.9282

b)
Critical value = 0.666

c) the answer is "a"
No because the absolute value of the correlation coefficient is greater than the critical value.

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