The Byrnes Corporation manufactures two types of calculators, the ACCT2000 for commercial use and the ACCT1000 for personal use. Budgeted and actual operating data for the year 2015 were as follows: Prior to the beginning of the year, a consulting firm estimated the total volume for calculators of the ACCT2000 and ACCT1000 category to be 250,000 units, but actual industry volume was 256,000 units. What is the total sales-volume variance in terms of the contribution margin What is the total sales-quantity variance in terms of the contribution margin What is the total sales-mix variance in terms of the contribution margin