A report shows that Covid-19 reduced household expenditure in Europe by 8% in 2020. Elsewhere, consumer spending also dropped significantly in 2020, with 4% seen in the United States, and 17% reported in China (Broom, 2021). After reading the report, Mr. Goh, a student of Singapore University of Social Sciences, was interested to find out how Covid-19 has affected the household spending in Singapore. Surprisingly, he found news saying that consumer spending among Singapore residents was resilient and at a similar level to 2019 (Choo, 2021). In order to have a better understanding of the impact of Covid-19 on household spending of Singapore residents, Mr. Goh decided to conduct a survey. He got a random sample of 32 students from Singapore University of Social Sciences, and collected data on their average monthly household expenditure in 2019 and 2020. Based on his own experience, he hypothesised that the household expenditure of Singapore residents in 2020 is lower than that in 2019.

Please refer to data below.

Average Monthly Household Expenditure (SG$)
Household No.	Year 2019	Year 2020
1	3100	3720
2	8250	5940
3	5430	5919
4	5900	5723
5	3900	3198
6	6300	7560
7	4800	5760
8	7400	6734
9	9210	8197
10	5950	6962
11	4390	3249
12	5520	3919
13	5810	4648
14	6360	5724
15	6490	7528
16	4290	3947
17	5550	4329
18	8280	8528
19	7360	6330
20	7810	6170
21	6745	7082
22	5630	4335
23	6530	4571
24	4570	5301
25	5790	6832
26	6390	6710
27	5210	4741
28	3670	2789
29	4420	4243
30	4690	5065
31	5630	5461
32	5910	4373

Qn1)

Describe 99% confidence interval of the mean monthly household expenditure in 2019 and 2020, respectively. Interpret and discuss whether Mr. Goh can conclude that the household expenditure of Singapore residents in 2020 is lower than that in 2019.