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Week 4 Assignment new
Intro to Biomedical Statistics (BST 322)
National University (US)
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- super helpful thank you for posting. quick note that everything looks correct except for 5c - the p-value is above .05, and the correlation coeff. is below the critical value, so the results are non significant
- great help
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1. Week 4 Assignment (1pt) For each correlation coefficient below, calculate what proportion of variance is shared the two correlated variables: a. b. 2. c. d. r 0 r2 0 r 0 r2 0 (1pt) For each coefficient of determination below, calculate the value of the correlation coefficient: a. b. 3. r 0 r2 0 r 0 r2 0 r2 0 r 0 r2 0 r 0 c. d. r2 0 r 0 r2 0 r 0 (1pt) Suppose a researcher regressed surgical length of stay (dependent variable) in the hospital on a scale of functional ability measured 24 hours after surgery. Given the following, solve for the value of the intercept constant and write out the full regression equation: Mean length of stay 6 mean score on scale slope Y a bx 6 a 0 (33) 6 a 3 9 a 4. (1pt) Using the regression equation calculated in Exercise 3, compute the predicted value of Y (length of hospital stay) for patients with the following functional ability scores: a. X 42 Y a bx Y 9 0 (42) Y 9 4 Y 5 5. b. X 68 Y a bx Y 9 0 (68) Y 9 6 (4 pts) Reexamine the Fellows Research Group data we used in week assignment (the excel file is named Mental Health and is also in this assignment area). Using this data set again, perform a correlation analysis using the General Practitioner Assessment of Cognition score as a predictor of the Mental Health Survey Score of all subjects. a. Plot the data with a regression line and perform a regression with the appropriate statistical test in StatCrunch. Copy and paste your graph and regression output into your Word document for full credit. Simple linear regression results: Dependent Variable: Mental Health Independent Variable: GPCOG Mental Health 43 0 GPCOG Sample size: 150 R (correlation coefficient) 0 0 Estimate of error standard deviation: 10 Parameter estimates: Week 4 Assignment Parameter Estimate Std. Err. Intercept 43 2 Slope Alternative DF 0 148 18 0 0 0 148 1 0 Analysis of variance table for regression model: Source DF Model SS MS 1 195 195 1 Error 148 17516 118 Total 149 0 17711 b. What is the correlation coefficient r and what is the coefficient of determination here? What does the coefficient of determination mean in this case? The correlation coefficient r is 0. This indicates that the correlation between GPCOG scores and Mental Health is a positive association. The coefficient of determination is 0 which implies that there is a variability in GPCOG scores as a predictor of the Mental Health. c. Is there a statistically significant correlation between cognition and mental health in this sample? Week 4 Assignment b. What is the correlation coefficient r and what is the coefficient of determination here? What does the coefficient of determination mean in this case? The correlation coefficient r is which indicates the correlation has a negative association. The coefficient of determination is 0. This means that there is about a variability in drug XAB dosage and cholesterol levels. c. Is there a statistically significant correlation between age and cholesterol in this sample? Since our of 0 is less than alpha 0 and our correlation coefficient of is greater than the given CV of 0, this proves our results to be significant. We accept the alternative hypothesis that there is a relationship between XAB dosage and cholesterol levels. d. What hypotheses did you test? H0: Intercept 0 HA: Intercept 0 H0: Slope 0 HA: Slope 0 e. Using StatCrunch, what is the predicted cholesterol level for a person taking a dose of 7 mg? Copy and paste your regression output from StatCrunch into your Word document for full credit. Predicted values: X value 7 Pred. Y 94 s.(Pred. y) C. for mean P. for new 27 (19, 170) 277) The predicted value of cholesterol level for a dose of 7 mg is 94. 7. (5 pts) A study the University of Montreal examined a new test to deepen the evaluation of mental states through the creation and validation of a practical measure, the Mental States Task (MST). The researchers examined many factors including age and the valid and reliable PANAS test. The data is in Week 4 Assignment an excel file named and is also in this assignment area. Using this data set, perform a correlation analysis using the age as a predictor of their PANAS score of all the subjects. a. Plot the data with a regression line and perform a regression with the appropriate statistical test in StatCrunch. Copy and paste your graph and regression output into your Word document for full credit. Simple linear regression results: Dependent Variable: PANAS Independent Variable: Age PANAS 0 0 Age Sample size: 125 R (correlation coefficient) 0 0 Estimate of error standard deviation: 0 Parameter estimates: Parameter Estimate Std. Err. Intercept 0 0 0 123 0 0 0 0 123 0 Slope Alternative DF Analysis of variance table for regression model: Source DF Model SS 1 5 MS 5 6 Error 123 107 0 Total 124 113 0 Week 4 Assignment undergrad GPA GREverbal 2 560 3 550 Subject 1 2 Subject 1: Y (0)2 (0)560 (0)55 Y 2 2 0 .495 Y 2 Subject 2: Y (0)3 (0)550 (0)65 Y 2 2 0 0 Y 3 9. GREquant 540 590 Motivation 55 65 (1pt) Using the following information for R2, k, and N, calculate the value of the F statistic for testing the overall multiple regression equation and determine whether F is statistically significant at the 0 level: a. R2 0, k 5, N 120 F ((1 0) (120 5 1)) F 0 ((0) (114)) F 0 0 F 3 Since our value of F is greater than the given table CV of 2, our results are significant. b. R2 0, k 3, N 64 F (0 3) ((1 0) (64 3 1) F 0 (0 60) F 0 0 4 Since our value of F is greater than the given CV of 2, our results are significant.
Week 4 Assignment new
Course: Intro to Biomedical Statistics (BST 322)
University: National University (US)
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