The Noise texture generates four different types of Procedural noise, and the settings give you the ability to produce a wide variety of noise effects. The four types of noise are:
Figure 1: A comparison of the four different noise types
Figure 2 shows the Noise texture connected to the DiffuseAmount of diffusion, or the reflection of light photons at different angles from an uneven or granular surface. Used for dull, non-reflecting materials or mesh emitters. channel of a Diffuse material. Figure 3 shows the settings that generate this noise pattern.
Figure 2
Figure 3: The Noise parameters in the Node Inspector