During the pandemic, the company launched various marketing breakthroughs to improve sales, including by allocating a budget for product promotions and events marketing. The company's management believes that the program can improve sales based on data recapitulated by the marketing team as follows:

Promotion (USD	Event (USD)	Sales (USD)
123	63	900
234	117	1000
321	161	1200
234	117	1050
231	116	876
234	117	778
432	216	1550
234	117	777
333	167	678
234	117	876

1) Prove whether there is an effect of these promotional programs and events on sales? Use the null hypothesis with a significance level of 5%! 2) Determine the sales projection model using multiple linear regression (multiple linear regression)? 3) How many sales if management budgeted USD 250 promotion and USD 125 for event? 4) If the event is considered unable to be carried out because it did not get permission during the pandemic, what is it? is there a difference in the effect of promotion on sales?