The standards for one case of Springfever Tonic are as follows: During the week ended March 13 , the following activity took place: 17,000 pound of raw materials were purchased for inventory at a cost of $4.15 per pound. 3,100 cases of finished product were produced. 17,000 pound of raw materials were used. 12,600 direct labor hours were worked at a total cost of $158,760. $70,560 of actual variable overhead costs were incurred. Required: Calculate each of the following variances. Note: Do not round intermediate calculations. Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance)