Proctor Cleaning Products manufactures a product using a process that allows for substitution between two materials, X-1 and Y-7. The company has the following direct materials data for its product: StandardcostsforoneunitofoutputX1Y768unitsofinputat$1.0012unitsofinputat$4.60 The following results were reported for January: Proctor has a policy of holding no inventories of any kind. Required: a. Compute materials price and efficiency variances. b. Compute materials mix and yield variances. Complete this question by entering your answers in the tabs below. Compute materials mix and yield variances. Note: Do not round intermediate calculations. Indicate the effect of each variance by selecting "F" for favorable, or "U" for unfavorable. If there is no effect, do not select either option