iPad 4:28 PM Library: th HI6007 Statistics for Business Decisions Past Exam 1 T3
ID: 3366859 • Letter: I
Question
iPad 4:28 PM Library: th HI6007 Statistics for Business Decisions Past Exam 1 T3.2017 QUESTION 1. Time series regression (10 marks). The table below presents the number of student attending the class during the semester Week Number of students 20 19 19 18 16 17 15 16 14 12 12 10 1 23 45 6 7 8 9 10 11 12 n Stotistics Multiple R R Square Adjusted R Square Standard Error 0.941 0.935 0.811 12 ANOVA 104.08 6.58 110.67 MS 104.08 158.12 187977E-07 0.66 Residual Total 10 Standard Upper 95% 22.32 0.70 Coefficients Eror tStat p.value Lower 95% Intercept Week 21.21 0.85 0.50 0.07 0.00 0.00 20.10 1.00 a) Write down the estimated regression equation b) Interpret the intercept c) Interpret the slope coefficient d) Interpret the correlation coefficient e) How well the model fits the data? (2 marks) (2 marks) (2 marks) (2 marks) (2 marks) HI6007 Final Exam T2 2017 2 of 6Explanation / Answer
Ans:
a)Regression eqn:
Number of students=-0.85*Week+21.21
b)If week=0,there will be on avaerage 21.21 number of students.
c)For addition of each week,there will be decrease of on average 0.85 students.
d)correlation cofficient=sqrt(0.941)=-0.97
(as slope is negative,so correlation cofficient will be negative)
There is strong negative correlation between number of students and week.
e)Cofficient of determination,R-square=0.941 or 94.1%
(R^2 indicates th fit of model)
It means that 94.1% of the variation in the dependent variable i.e. number of students is explained by the independnet variable i.e. week.
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