## Construct a 95% confidence interval estimate for the mean train ticket sales for a month with a petrol price of \$2.30/litre and 90%of the trains being on time.

a. Use Excel’s “Data Analysis” functions to determine the predictive model for the

above data. [8 marks]

b. Interpret the meaning of the slope coefficient, b1 and b2. [2 marks]

c. Explain why coefficient b0 would have no practical meaning in the context of this

problem. [1 marks]

d. Predict the train ticket sales for a month with a petrol price of \$1.30/litre and 90% of

trains being on time. [4 marks]

e. Construct a 95% confidence interval estimate for the mean train ticket sales for a

month with a petrol price of \$2.30/litre and 90%of the trains being on time.

[4 marks]

f. Determine whether there is a significant relationship between ticket sales and the two

independent variables at the 0.05 level of significance. [5 marks]

g. Interpret the meaning of the p-value. [2 marks]

h. Calculate the coefficient of multiple determination, R2 and interpret its meaning.

2

[4 marks]

i. Calculate the adjusted R2. [2 marks]

j. Perform a residual anlaysis on your results and determine the adequacy of this model.

[3 marks]

k. Plot the residuals against the weekdays(time). Is there evidence of a pattern in the

residuals? Explain. [4 marks]

l. Determine the Durbin-Watson statistics. [8 marks]

m. At the 0.05 level of significance, is there evidence of positive autocorrelation in the

residuals?