The standards for one case of liquid weed killer are as follows: Direct materials Direct labor Variable overhead (based on machine hours) 7 lb @ $8.25/lb 4 hr @ $17.6/hr 1.3 hr@$6.05/hr During the week ended May 6, the following activity took place 4,224 machine hours were worked. 24,179 lb of raw material were purchased for inventory at a total cost of $203,587 3,420 cases of finished product were produced. 23,816 lb of raw material were used. 13,379 labor hours were worked at an average rate of $17.88 per hour. $24,668 actual variable overhead costs were incurred. Required: Calculate each o he ollowing variances. Do not round intermediate calculations Indicate the effect of each variance by selecting unfavorable, and "None" for no effect (i.e., zero variance).) E for avo able or a. Price variance for raw materials purchased. b. Raw materials usage variance. c. Direct labor rate variance. d. Direct labor efficiency variance e. Variable overhead spending variance. f. Variable overhead efficiency variance