normspec

R2026b

Normal density plot shading between specifications

Syntax

p = normspec(specs)

p = normspec(specs,mu,sigma)

p = normspec(specs,mu,sigma,region)

p = normspec(ax,___)

[p,h] = normspec(___)

Description

p = normspec(specs) plots the standard normal density, shading the portion inside the specification limits given by the two-element vector specs, and returns the probability p of the shaded area. If there is no lower specification bound, specify the first element of specs as –Inf. If there is no upper specification bound, specify the second element of specs as Inf.

p = normspec(specs,mu,sigma) uses a normal density with parameters mu and sigma.

p = normspec(specs,mu,sigma,region) specifies the shading region as either "inside" or "outside" the specification limits. The default is "inside".

p = normspec(ax,___) plots into the axes specified by ax instead of the current axes (gca) using any of the input argument combinations in the previous syntaxes. (since R2024a)

[p,h] = normspec(___) also returns a column vector of chart line objects h. Use h to modify properties of a specific chart line after you create the chart. For a list of properties, see Line Properties.

Examples

Create Standard Normal Density Plot Shading Inside of Limits

Create a standard normal density plot, shading the portion inside the specification limits [-1,1].

p = normspec([-1,1])

p = 
0.6827

Create Normal Density Plot Shading Outside of Limits

Create a normal density plot, shading the portion outside the specification limits.

For example, consider a production process that fills cans of paint. The average amount of paint in any can is 1 gallon, but variability in the process produces a standard deviation of 2 ounces (2/128 gallons). Create a normal density plot, shading the portion corresponding to the probability that the cans will be filled under specification by 3 or more ounces.

p = normspec([1-3/128,Inf],1,2/128,'outside')

p = 
0.0668

Input Arguments

specs — Specification limits

two-element numeric vector

Specification limits, specified as a two-element numeric vector. At least one element must be finite. If there is no lower specification bound, specify the first element of specs as –Inf. If there is no upper specification bound, specify the second element of specs as Inf.

Data Types: single | double

mu — Mean

0 (default) | scalar value

Mean of the normal distribution, specified as a scalar value.

Data Types: single | double

sigma — Standard deviation

1 (default) | positive scalar value

Standard deviation of the normal distribution, specified as a positive scalar value.

Data Types: single | double

region — Shading region

"inside" (default) | "outside"

Shading region, specified as either "inside" or "outside". The function normspec shades the region either "inside" or "outside" the specification limits.

ax — Target axes

Axes object

Since R2024a

Target axes, specified as an Axes object. If you do not specify the axes, then normspec uses the current axes (gca).

Output Arguments

p — Probability of shaded area

nonnegative scalar value

Probability of the shaded area, returned as a nonnegative scalar value.

h — One or more chart line objects

scalar | vector

One or more chart line objects, returned as a scalar or vector. These objects are unique identifiers that you use to query and modify properties of a specific chart line. For a list of properties, see Line Properties.

Version History

Introduced before R2006a

R2024a: Specify target axes

Specify the target axes for the plot by using the ax input argument.