Eye chart smaller symbols until the person cannot identify the symbols. The smallest symbols that can be reliably identified is considered the person's visual acuity. The Snellen chart is the most widely used. Alternative types of eye charts include the logMAR chart, Landolt C, E chart, Lea test, Golovin–Sivtsev table, the Rosenbaum chart, and the Jaeger chart. Charts display several rows of optotypes, which are standardized symbols for testing vision. Optotypes are usually letters, numbers, or geometric symbols. Each row of the chart depicts optotypes of a different size. Typically the largest optotypes are in the top row. The optotypes become progressively
X̅ and s chart on the other hand, the sample variability is "not" in statistical control, then the entire process is judged to be not in statistical control regardless of what the formula_7 chart indicates. When samples collected from the process are of unequal sizes (arising from a mistake in collecting them, for example), there are two approaches: X̅ and s chart In statistical quality control, the formula_7 and s chart is a type of control chart used to monitor variables data when samples are collected at regular intervals from a business or industrial process. The chart is advantageous in the following situations: The