Heritage Furniture Co. uses a standard cost system. One of the company's most popular products is an oak entertainment center that looks like an old ice box but houses a television, stereo, or other electronic components. The per-unit standard costs of the entertainment center, assuming a "normal" volume of 1,000 units per month, are as follows: During October, 800 entertainment centers were scheduled and produced at the following actual unit costs: Compute the following cost variances for the month of October: Materials price variance Materials quantity variance Labor rate variance Labor efficiency variance As a manager, would you investigate these variances? Explain