Recently, some internet platform companies have been offering a series of services and incentives to support and empower "street-stall economy": the "same-day distribution" service by Suning provides RMB 100 billion yuan of traceable high-quality local goods across the country, involving local specialties, fresh produce, original agricultural products, and other categories; 10000 refrigerators are provided in Carrefour supermarkets and Suning convenience stores, and night market stall vendors can apply for their free cold-chain storage service within 3 km. Suning convenience stores play the role of "capillary vessels", where the refrigerators and freezers in the stores are open to the surrounding street vendors to store wares for free trial, under the condition of ensuring its own operation. Besides the supply of goods, the "street-stall economy" also needs financial support to upgrade its development. It is reported in data that 96% of the vendors are short of supply funds, which is no more than RMB 100000 yuan, and "one helping hand can make them live". Each platform has tailored its financial services to support stall owners. Alibaba 1688 provides 70 billion yuan of "Sincere e Credit", an interest-free loans service, to support stall vendors to purchase goods on credit from 1688 platform. Jingdong provides up to RMB 100000 yuan interest-free credit for each store owner, fully supporting the street stall and local small store economy.

1. (a)Please come up with a question about linear regression equation in this background. The sample data of two groups must be listed. The sample size is

n=20-the ending number of your student number. (20 points) compulsory question)

1. (b)Check the existence of the linear trend in question (a); The significance level is 5%. (20 points) (compulsory question)