EPI/STA 553 Principles of Statistical Inference II Fall 2006 Regression: Testing Assumptions December 4‚ 2006 Linearity The linearity of the regression mean can be examined visually by plots of the residuals against any of the independent variables‚ or against the predicted values. Chart 1 shows a residual plot that reveals no Chart 2 C hart 1 0.4 0.4 0.3 0.3 0.2 0.1 0.1 Residual Residual 0.2 0.0 -0.1 0.0 -0.1 -0.2 -0.2 -0.3 -0.3 -0.4 -0.5
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Regression Analysis Exercises 1- A farmer wanted to find the relationship between the amount of fertilizer used and the yield of corn. He selected seven acres of his land on which he used different amounts of fertilizer to grow corn. The following table gives the amount (in pounds) of fertilizer used and the yield (in bushels) of corn for each of the seven acres. |Fertilizer Used |Yield of Corn | |120
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Types of regression and linear regression equation 1. The term regression was first used as a statistical concept in 1877 by Sir Francis Galton. 2. Regression determines ‘cause and effect’ relationship between variables‚ so it can aid to the decision-making process. 3. It can only indicate how or to what extent variables are associated with each other. 4. There are two types of variables used in regression analysis i.e. The known variable is called as Independent Variable and the variable which
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Topic 8: Multiple Regression Answer a. Scatterplot 120 Game Attendance 100 80 60 40 20 0 0 5‚000 10‚000 15‚000 20‚000 25‚000 Team Win/Loss % There appears to be a positive linear relationship between team win/loss percentage and game attendance. There appears to be a positive linear relationship between opponent win/loss percentage and game attendance. There appears to be a positive linear relationship between games played and game attendance. There does not appear to be any relationship
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l Regression Analysis Basic Concepts & Methodology 1. Introduction Regression analysis is by far the most popular technique in business and economics for seeking to explain variations in some quantity in terms of variations in other quantities‚ or to develop forecasts of the future based on data from the past. For example‚ suppose we are interested in the monthly sales of retail outlets across the UK. An initial data analysis would summarise the variability in terms of a mean and standard
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Hypnotherapy and Counselling Skills Assignment Module 4 I would start by evaluating why Mr X has come to me for hypnotherapy‚ what he hoped to achieve and what is his reason for seeking therapy. Has he made the appointment for himself? I would ask lots of questions about his relationship with his mother; ascertain if this is where his negative self- beliefs have come from and what their relationship dynamics are. There is no mention of Mr X’s father‚ has his death or leaving his mother been
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Only a few sessions of hypnotherapy can help the individual in achieving an improved sense of self with enhanced self-confidence and sense of being composed‚ self-assured and successful. following a visual PMR to achieve relaxation‚ suggestions using visual sub modalities‚ metaphor
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Cox Regression Models Questions with Answers Worked Example An investigation is carried out into popularity of new cars being bought in the showroom of a Mercedes dealer. Data recorded for each car included colour‚ engine size and car type. A Cox proportional hazards model was fitted to the data and the results are given below: Write down the Cox hazard function according to this model. With regards to the model you have written down above state the following: • To which class of car does the
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http://www.mathsisfun.com/data/standard-normal-distribution-table.html (Z table) http://www.sjsu.edu/faculty/gerstman/StatPrimer/t-table.pdf (t table) Critical Values (Z) Level of Significance 1% 2% 4% 5% 10% Two Tailed ±2.56 ±2.32 ±2.05 ±1.96 ±1.64 Right tailed +2.32 +2.05 +1.75 +1.64 +1.28 Left tailed -2.32 -2.05 -1.75 -1.64 -1.28 Q1) A cinema hall has cold drinks fountain supplying Orange and Ditzy Colas. When the machine is turned on‚ it fills a 550ml cup with 500ml of the
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Assignment # 1 Forecasting (Total marks: 100) Following 10 Problems are for submission Problem 1: [12] Registration numbers for an accounting seminar over the past 10 weeks are shown below: |Week 1 2 3 4 5 6 7 8 9 10 | |Registrations 24 23 28 30 38 32 36 40 44 40 | a) Starting with week 2 and ending with
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