# R

## R^{2}

See R-squared.

## Ratio analysis

Ratio analysis is analyzing a company based on calculating a set of financial ratios. Common financial ratios include:

- current ratio
- return on assets
- return on equity
- net profit margin
- debt to equity ratio

## Return on assets

Return on assets (ROA) is a financial ratio of how profitable a company is based on its assets. The most common formula divides net income by total assets. ROA is shown as a percentage.

Assume a company has net income of $5,000 and total assets of $40,000. The ROA is 5,000 / 40,000 = 12.5%

## Return on equity

Return on equity (ROE) is a financial ratio of how profitable a company is based on its stockholders’ equity. The ROE formula divides net income by total equity. ROE is shown as a percentage.

Assume a company has net income of $5,000 and total equity of $25,000. The ROE is 5,000 / 25,000 = 20.0%

## Return on investment

Return on investment (ROI) is a financial ratio of how profitable a project is based on its initial investment. The ROI formula divides net profit by total investment. Net profit equals Current Value of Investment + Income – Initial Investment and Costs. ROI is always shown as a percentage.

Assume Zebra Co. purchased stock for $50,000. After one year, the stock paid dividends of $1,500 and was worth $55,000. The net profit is 55,000 + 1,500 – 50,000 = 6,500. So, the ROI is 6,500 / 50,000 = 13.0%

## Return on sales

Return on sales (ROS) is a measure of how much profit is produced per dollar in sales revenue. ROS divides net income by net sales. ROS is shown as a percentage.

Assume a company has net income of $5,000 on net sales of $80,000. The ROS is 5,000 / 80,000 = 6.25%. For every dollar of sales, the company produces 6.25 cents.

## Revenue

Revenue occurs when a business receives assets by selling a product or service. Revenues are one of the five types of accounts. Revenues are included in the income statement. Revenues are also called income or gains.

## ROA

See return on assets.

## ROE

See return on equity.

## ROI

See return on investment.

## ROS

See return on sales.

## R-squared

R-squared (r^{2}) is a statistical measure called the coefficient of determination. The r^{2} is a measure of regression of the proportion of the variability of the dependent variable explained by changes in the independent variable.

So, if r^{2} = 0.70, then 70% of the variability of the dependent variable is explained by the inputs. For example, an S&P 500 index fund has returns with an r^{2} = 1.00 versus the underlying S&P 500 index. So, all the fund returns are explained by the variability in the index.

## Rule of 72

The Rule of 72 is an estimate of how fast an investment doubles given a fixed interest rate. It approximates a compound interest problem of an account that grows exponentially. Rule of 72 formula: Years to double = 72 / Interest Rate.

For example, if an account earns 8%, how fast will the account double? 72 / 8 = 9 years. So at 8%, an investment would double in approximately 9 years. Note: the 8% is used in the formula as a whole number, or 8.