Many economists view the natural rate of unemployment as the level observed when real gdp is given by the position of the long-run aggregate supply curve there can be positive unemployment in this situation because a. corporations need the presence of some unemployment to keep workers "in line." b. business cycles are an inherent feature of the economy causing cyclical unemployment to naturally occur. c. in a free society some people will always prefer idleness over work. d. information is costly and rigidities always exist causing some types of unemployment (frictional and structural) to occur even in the long run after everyone in the economy has fully adjusted to any changes.

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