Mendel’s experiments had a large sampling size, which gave greater credibility to the data that he collected.

Odd One Out: Experiments had a small sampling size

Explanation:

Mendel's Laws of Inheritance:
1. Law of Segregation: During gamete formation, the alleles for each gene segregate from each other so that each gamete carries only one allele for each gene.
2. Law of Independent Assortment: Genes for different traits segregate independently during the formation of gametes.

a) Conducted hybridisation experiments on Pisum sativum for seven years (1856 - 1863)
This statement is in line with Mendel's Laws of Inheritance. Gregor Mendel conducted experiments on Pisum sativum (pea plants) for seven years, observing the inheritance patterns of different traits such as seed color, seed shape, and flower color. He carefully crossed true-breeding plants with contrasting traits and analyzed the traits of the offspring. This experimentation led to the formulation of Mendel's Laws of Inheritance.

b) First time statistical analysis and mathematical logic were applied to problems in biology
This statement is also in line with Mendel's work. Mendel was the first to apply statistical analysis and mathematical logic to the field of biology. He quantitatively analyzed the results of his experiments and used mathematics to deduce the patterns of inheritance. This approach laid the foundation for the field of genetics.

c) Experiments had a small sampling size
This statement is the odd one out. Mendel's experiments were conducted with a large number of pea plants, not a small sampling size. He carefully selected 14 true-breeding pea plant varieties and performed a large number of crosses to ensure statistical significance and reliable results. Mendel's extensive experimentation allowed him to observe consistent patterns of inheritance and formulate his laws.

d) He selected 14 true-breeding pea plant varieties
This statement is in line with Mendel's work. Mendel selected 14 true-breeding pea plant varieties with distinct traits to perform his experiments. By crossing these varieties, he was able to study the inheritance patterns of specific traits and establish the principles of dominance, segregation, and independent assortment.

In conclusion, the odd one out is "c) Experiments had a small sampling size." Mendel's experiments involved a large number of pea plants, not a small sampling size, to ensure reliable and statistically significant results.