kindly solve to the simplest understanding... the topic is under performance management

Planning and operational variance (Advance standard costing) Example 1 - Performance Standards 3kg/ unit for $5/kg Actual results Required: Prepare the variance using basic variance analysis and assess whether the purchasing manager and production manager individually have done a good or bad job. Additional information. After further consideration the standards have been revised to reflect changes that have occurred overtime. The revised standard usage in now expected to be 3.1kg due to a poor harvest leading to poorer quality inputs. In addition, due to adverse movement in the exchange rate the material cost have changed. It is now expected that each kg will cost $5.15 Required: Prepare an analysis of variance into both planning and operational elements and assess the performance of the purchasing manager and production manager individually