# Blog

## Modified Duration

Our forum contains hundreds of questions about duration. Duration often vexes new candidates, in part because there are several types. Let's first settle a confusion: the units of all durations are years (time). So, regardless of which duration, we can typically say something like "The bond's duration is 4.52 years." I taught duration several years...

## What Is a Z Table?

Functions based on the normal distribution are easy to retrieve in code or excel, so we do not really need z tables anymore, in practice. But we still want to understand the z table. Why? Because the popular exam calculators (TI BA II+ and HP 12c) do not include z table functionality, so we do... ## Statistical Inference: Hypothesis Testing and Confidence Intervals

320.1. Recently 25 banks were surveyed. Their sample average total capital is 8.40% (i.e., Tier 1 plus Tier 2 as a percentage of risk-weighted assets, RWA) with a sample standard deviation of 1.0%. Our one-sided null hypothesis is that the population's "true" average total capital is less than or equal to 8.0%. With 95.0% confidence,...

## Economic Capital (Schroeck)

Learning outcomes: Evaluate a bank’s economic capital relative to its level of credit risk. Identify and describe important factors used to calculate economic capital for credit risk: probability of default, exposure, and loss rate. Questions: 505.1. According to Schroeck, economic capital is an estimate of the overall level of capital necessary to guarantee the solvencyof...