GlassRI 02: Grouping refractive index data by SKM2 using a calculator
 

Assume that five fragments have been recovered from a suspect.  These fragments have RI values (each the average of several GRIM measurements) given by:

 

1.52428

1.52419

1.52430

1.52420

1.52427

 

Six control samples submitted have RI values of

 

1.52419

1.52421

1.52414

1.52422

1.5242

1.52426

 

which have a mean value = 1.52420 and standard deviation = 3.9310-05


Group the recovered samples "by eye" and check the validity of the grouping by calculating the value
l*  for the SKM2 algorithm. 

Use the standard deviation of the control as an estimate for the standard deviation of the recovered group.
 

Video Answer: l* = 8.28, 1 group