Sales at a fast-food restaurant average $6,000 per day. the restaurant decided to introduce an advertising campaign to increase daily sales. in order to determine the effectiveness of the advertising campaign, a sample of 49 day's sales were taken. the sample showed an average daily sales of $6,300. from past history, the restaurant knew that its population standard deviation is about $1,000. if the level of significance is 0.01, do the sales increased as a result of the advertising campaign?

Xinhong company is considering replacing one of its manufacturing machines. the machine has a book value of $39,000 and a remaining useful life of 5 years, at which time its salvage value will be zero. it has a current market value of $49,000. variable manufacturing costs are $33,300 per year for this machine. information on two alternative replacement machines follows. alternative a alternative b cost $ 115,000 $ 117,000 variable manufacturing costs per year 22,900 10,100 1. calculate the total change in net income if alternative a and b is adopted. 2. should xinhong keep or replace its manufacturing machine