**GlassRI 04:
Calculation of likelihood ratio from recovered glass fragments
**

Assume that five fragments have been recovered from a suspect's upper clothing approximately 2 hrs after a breaking incident. 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 = 3.93×10^{-05}

Group the recovered samples "by eye" and check the validity of the grouping by calculating the value l

Apply the required test for a match between recovered and control fragments.

**Hint: **See tutorial question GlassRI 03 for the same calculation.

Calculate
the likelihood ratio for obtaining the evidence given the competing hypotheses
that the suspect was involved in breaking the window and that the accumulation
of glass on his clothes occurred purely by chance.

Formulate your statement.

Video Answer: As
GlassRI02 and GlassRI03, *L *= 10,000