Ratio analysis involves calculating and interpreting numerical relationships derived from financial statements to assess a company's financial health and performance. There are various types of ratios that can be calculated including liquidity ratios to test short-term financial position, solvency ratios to test long-term financial position, activity ratios related to asset utilization, and profitability ratios related to earnings. Some key individual ratios discussed in the document are the current ratio, quick ratio, debt-equity ratio, inventory turnover ratio, gross profit ratio, and operating ratio.