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Published byBerkant Erdem Modified over 6 years ago
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WARM – UP Can you accurately predict your TEST grade based on your QUIZ grade? STUDENT QUIZ TEST 1 2 3 4 5 6 7 8 88 84 100 92 70 80 81 95 102 94 90 85 99 97 Describe the association between Quiz Grades and Test Grades. Write the equation of the line of regression. Use this model to predict a Test Grade from a Quiz grade of 50. Is this a good model?
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STUDENT QUIZ TEST 1 2 3 4 5 6 7 8 88 84 100 92 70 80 81 95 102 94 90 85 99 97 Describe the association between Quiz Grades and Test Grades Write the equation of the line of regression. Use this model to predict a Test Grade from a Quiz grade of 50. Is this a good model? TEST Grade Residuals QUIZ Grade QUIZ Grade TEST = (QUIZ) = = (50)
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WARM – UP # Hours of Study Test Grade .5 3 1.5 2 1 72 98 82 89 76 73 Does a significant relationship exist between number of hours studying and test grades? H0: β1 = 0 Ha: β1 ≠ 0 β=True Slope of the linear relationship. Lin Reg t-Test Since the p-value is less than 0.05, we REJECT H0. There is sufficient evidence to conclude that # hours of study and Test grades are related.
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Is there a relationship between the amount of lead verses the amount of Zinc present in fish? State Hypothesis and Conclusion. Dependent Variable is: Zinc R-squared = 85.7% s = with 8 – 2 = 6 degrees of freedom Variable Coefficient SE(Coeff) T-ratio P-Value Intercept Lead Because the p-val < 0.05 Reject Ho. There is evidence to conclude that a relationship exists b/t lead and zinc content in fish.
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Regression Inference C.I.
To estimate the rate of change/slope, we use a Confidence Interval. The formula for a confidence interval for 1 is:
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WARM – UP STUDENT QUIZ TEST 1 2 3 4 5 6 7 8 88 84 100 92 70 80 81 95 102 94 90 85 99 97 Find the 95 % Conf. Interval for the Rate of Improvement from the Quiz to the Test . Dependent Variable is: Test R-squared = 35.3% s = with 8 – 2 = 6 degrees of freedom Variable Coefficient SE(Coeff) T-ratio P-Value Intercept Quiz We can be 95% confident that for every additional point increase in quiz grade your test grade is predicted to be to points higher.
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Powerboat Registrations In Thousands
EXAMPLE: Manatees living off the coast of Florida are often killed by powerboats. Here are data from 1984 – 1990 Powerboat Registrations In Thousands Manatees Killed 459 24 585 33 614 645 39 675 43 711 52 719 51 Dependent Variable is: Manatees R-squared = 98.2% s = with 7 – 2 = 5 degrees of freedom Variable Coefficient SE(Coeff) T-ratio P-Value Intercept Boats <0.0001 Find the 95% confidence interval for the rate at which the Manatee deaths change with regards to powerboat registration. We can be 95% confident that for every additional 1000 powerboat registered, between and more Manatees are killed.
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Estimate the Rate of change for the relationship between lead and zinc using a 99% Confidence Interval Metal Concentrations in 1999 Spokane River Fish Samples (concentrations in parts per million (ppm) Source: WA State Dept. of Ecology report) Lead Zinc Dependent Variable is: Zinc R-squared = 85.7% s = with 8 – 2 = 6 degrees of freedom Variable Coefficient SE(Coeff) T-ratio P-Value Intercept Lead We can be 99% confident that the true slope of the relationship between lead and zinc is between .
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Show that the p-value is 0
Show that the p-value is by using the t formula and calculating the p-value. Lead Zinc Dependent Variable is: Zinc R-squared = 85.7% s = with 8 – 2 = 6 degrees of freedom Variable Coefficient SE(Coeff) T-ratio P-Value Intercept Lead SE(b1)
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HW Page 661: 11, 12, 16-18
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Is there a relationship between the amount of lead verses the amount of Zinc present in fish? State Hypothesis and Conclusion . Metal Concentrations in 1999 Spokane River Fish Samples (concentrations in parts per million (ppm) Source: WA State Dept. of Ecology report) Lead Zinc Dependent Variable is: Zinc R-squared = 85.7% s = with 8 – 2 = 6 degrees of freedom Variable Coefficient SE(Coeff) T-ratio P-Value Intercept Lead P-value Because the p-val < 0.05 there is significant evidence to conclude that a relationship exists b/t lead and zinc content in fish.
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Performing a Linear Regression t-Test from the Calculator
Is there a relationship in the amount of lead verses the amount of Zinc present in fish? Lead Zinc STAT Test LinRegTTest Because the p-val < 0.05 there is significant evidence to conclude that a relationship exists b/t lead and zinc content in fish.
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Is there a relationship between the amount of lead verses the amount of Zinc present in fish? State Hypothesis and Conclusion . Metal Concentrations in 1999 Spokane River Fish Samples (concentrations in parts per million (ppm) Source: WA State Dept. of Ecology report) Lead Zinc Seb = P-value = Because the p-val < 0.05 there is significant evidence to conclude that a relationship exists b/t lead and zinc content in fish.
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