During February the Lungren ManufacturingCompany's costing system reported several variances that the production manager was surprised to see. The following information is for the manufacture of gardengates, its onlyproduct:

1. Direct materials ratevariance, $800 unfavourable.

2. Direct materials efficiencyvariance, $1,800 favourable.

3. Direct manufacturing labour ratevariance, $4,000 favourable.

4. Direct manufacturing labour efficiencyvariance, $600 unfavourable.

Required:

a. Provide the manager with some ideas as to what may have caused the ratevariances.

b. What may have caused the efficiencyvariances?