Data

Type

Tracking

Sample

Charts

Variable Data

Individuals

Process level (individuals)

Subgroup size = 1 Data point >30

I Chart

Process variation (moving range)

Subgroup size = 1 Data point >30

MR Chart

Process level and variation

-

I-MR Chart

Subgroups

Process level (means)

5-10 subgroups

Xbar Chart

Process variation (ranges)

5-10 subgroups
Small subgroups (<= 5)

R Chart

Process variation (standard deviations)

5-10 subgroups
Large subgroups (<= 5)

S Chart

Both

-

XBar-R Chart

Both

-

XBar-S Chart

Both

-

I-MR-R/S Chart

Non-weighted

Process level (Minor shifts)

Subgroups >= 1
Large samples

MA Chart

Weighted

Process level (Minor shifts)

Subgroups >= 1
Large samples

EWMA Chart

Attribute Data

Defectives
(Defective product)

Number of defectives

Equal subgroup size

NP Chart

Percentage of defectives

Different (or same) subgroup size

P Chart

Defects
(Product can have more than one defect)

Number of defects

Equal subgroup size

C Chart

Number defects per unit

Different (or same) subgroup size

U Chart