Asure Co. is a small car distribution dealer located in the capital. Asure would like to evaluate the performance of its marketing activities during the past year. Following is the rating of marketing aggressivity (X) and sales performance (Y) of 8 sales staffs in Company PGB in the past year:

X	30	17	35	28	42	25	19	29
Y	35	31	43	46	50	32	33	42

a. What statistical method can be applied for this study? Explain your answer (2 points) b. What is the hypothesis of the study? (2 points) c. At a 10% significance level, is there any correlation between marketing aggressivity and sales performance? (8 points)

4B (13%) Based on the data of air pollution in New York in 2019, the Environmental Protection Agency (EPA) decided to publish a new stricter regulation effective in January 2020 to reduce hydrocarbon pollution. EPA wants to evaluate whether the new regulation makes significant differences in reducing pollution. EPA collects data of monthly hydrocarbon pollution level as follows:

	JAN	FEB	MAR	APR	MAY	JUNE	JULY	AGT	SEPT
2019	7.3	6.0	5.4	5.9	3.9	5.7	6.9	7.6	6.3
2020	5.3	6.1	5.6	5.7	3.7	4.7	6.1	7.2	6.4

	OKT	NOV	DES
2019	5.8	5.1	5.9
2020	5.7	4.9	5.8

a. What statistical method can be applied for this study? Explain your answer (2 points) b. What is the hypothesis of the study? (2 points) c. At a 5% significance level, is the performance between the two sample groups significantly different? (9 points)