Required: 1. Check your worksheet by changing the revenue in cell D4 to $16.00; the cost of ingredients in cell D5 to $6.50; and the wages and salaries in cell B6 to $10,000. The activity variance for net operating income should now be $850 U and the spending variance for total expenses should be $410 U. If you do not get these answers, find the errors in your worksheet and correct them. a. What is the activity variance for revenue? Explain this variance. b. What is the spending variance for the cost of ingredients? Explain this variance. 2. Revise the data in your worksheet to reflect the results for the following year: Using the flexible budget performance report, briefly evaluate the company's performance for the year and indicate where attention should be focused