FDC Statistical Analysis & Population Genetics 2

Question 1

A Likelihood Ratio (LR) in forensic DNA statistics compares:

Accepted Answer

The probability of the evidence given the prosecution hypothesis versus the probability of the evidence given the defense hypothesis

Answer

The probability of a match given innocence versus guilt

Answer

The combined profile frequency across two separate loci

Answer

The ratio of heterozygote to homozygote frequencies

Question 2

When a DNA mixture is observed and the contributor number is uncertain, which statistical approach can account for all possible numbers of contributors?

Accepted Answer

Probabilistic genotyping software using continuous models

Answer

The product rule applied to all alleles present

Answer

The ceiling principle with average allele frequencies

Answer

A simple RMP calculated from visible alleles only

Question 3

The Combined Probability of Inclusion (CPI) in mixture statistics represents:

Accepted Answer

The probability that a randomly selected, unrelated person could be a contributor to the mixture

Answer

The probability that the known contributor is the source of the major component

Answer

The likelihood ratio favoring inclusion of a specific individual

Answer

The number of individuals whose profiles are consistent with the mixture

Question 4

Which of the following best describes the 'sampling uncertainty' concern in forensic DNA statistics?

Accepted Answer

Allele frequencies estimated from finite reference databases may not perfectly represent the true population frequencies

Answer

The DNA sample collected at the crime scene may be too small to yield a full profile

Answer

Random errors in the capillary electrophoresis instrument affect allele sizing

Answer

Uncertainty about which suspect contributed to the mixed profile

Question 5

If a forensic analyst calculates an RMP of 1 in 10 quadrillion for a 20-locus CODIS profile, this statistic means:

Accepted Answer

The profile is expected to occur in approximately 1 out of every 10 quadrillion unrelated individuals

Answer

The probability that the suspect committed the crime is 10 quadrillion to one

Answer

Laboratory error is 1 in 10 quadrillion

Answer

The match probability exceeds the world population and is therefore meaningless

Question 6

In forensic DNA statistics, the 'ceiling principle' proposed by NRC I involved:

Accepted Answer

Using a minimum allele frequency of 5% (or 10%) regardless of the observed frequency to provide conservative estimates

Answer

Capping the RMP at 1 in 1 billion regardless of calculated values

Answer

Limiting the number of loci used in calculations to avoid overclaiming

Answer

Applying an upper confidence limit to the population database allele counts

Question 7

Under the NRC II framework, which major population databases are typically used for U.S. forensic DNA statistics?

Accepted Answer

Caucasian, African American, and Hispanic reference populations

Answer

Asian, European, and Middle Eastern populations only

Answer

A single universal population database

Answer

Individual state-level population databases