In the presence of serial correlation:.a. estimated standard errors remain valid. b. estimated test statistics remain valid. c. estimated OLS values are not BLUE. d. estimated variance does not differ from the case of no serial correlation.

Sales at a fast-food restaurant average $6,000 per day. the restaurant decided to introduce an advertising campaign to increase daily sales. to determine the effectiveness of the advertising campaign, a sample of 49 days of sales were taken. they found that the average daily sales were $6,300 per day. from past history, the restaurant knew that its population standard deviation is about $1,000. if the level of significance is 0.01, have sales increased as a result of the advertising campaign? multiple choicea)fail to reject the null hypothesis.b)reject the null hypothesis and conclude the mean is higher than $6,000 per day.c)reject the null hypothesis and conclude the mean is lower than $6,000 per day.d)reject the null hypothesis and conclude that the mean is equal to $6,000 per day.expert answer

What do you think: would it be more profitable to own 200 shares of penny’s pickles or 1 share of exxon? why do you think that?

After jeff bezos read about how the internet was growing by 2,000 percent a month, he set out to use the internet as a new distribution channel and founded amazon, which is now the world's largest online retailer. this is clearly an example of a(n)a. firm that uses closed innovation. b. entrepreneur who commercialized invention into an innovation. c. business that entered the industry during its maturity stage. d. exception to the long tail business model