Question 4 The following data in the sales in ice-cream was collected in the past 2 years in each quarter. Time period Sales (in HK$000) 15t Q, 2020 80 2r":l Q, 2020 85 3'"d Q, 2020 82 4'\" Q. 2020 _ 1'6 15t Q. 2021 78 2"rd Q, 2021 88 3"\"I Q. 2021 85 4"\" CL 2021 30 Total 854 a. Find out the seasonal index for 1st Q to 4'\" 0 using the above data. {15 marks) 0. Find out the de-seasonalized value for 1St Q to 4'h Q of 2021 (0 marks} c. According to your answer above, which quarter has the highest sales after taking away the seasonal effect? (2 marks) Please quote relevant formula and show the steps when working out your answers. wJI:LI "-I- --lI-|':ll