A research report shows that there is a trend that more people prefer to live in 4-room or bigger HDB flats. To investigate whether this finding is true, you have collected the quarterly number of re-sale flat applications from Quarter 1 of 2007 to the recent Quarter 2 of 2019. The data is given in the Excel data file "BUS105_GBA_resale". Please conduct some of your own research and use the Excel software to answer the following:

Question 1 (a) Use relevant numerical measures and graphical representations to have some preliminary observations of the 3-room and 4-room re-sale flat applications. (20 marks)

(b) Show 95% confidence intervals for the average number of 4-room and 3-room re-sale flat applications, respectively. Discuss whether you can conclude that there are more 4-room re-sale flat applications than the 3-room re-sale flat applications. (13 marks)

(c) Apply an appropriate test of hypothesis to determine if there are more 4-room re-sale flat applications than the 3-room re-sale flat applications. (12 marks)

(d) Summarise your analysis and findings regarding the research question whether there is a trend that more people prefer to live in 4-room or bigger HDB flats. (25 marks)