LAB LECTURE 3

Chi square test

Used to determine how well observed phenotypic ratios match expected ones given hypothesized pattern of inheritance

When is hypothesized pattern of inheritance supported?

When results indicate that difference between O and E could be due to chance

When is hypothesized pattern of inherited rejected?

When results indicate that difference between O and E are not likely to be due to chance

Null hypothesis

Difference found between observed and expected distribution is not significant

If critical x² <= calculated x²

Then we reject the null hypothesis because it is a significant difference

What p-value means

0.05; we are allowing for 5% error in accepting a hypothesis that should really be rejected

• 95% confidence in “failing to reject” H₀

Metric system is based on

Power of 10s

Order of magnitude

Relative size of a number, often used in comparison between 2 numbers

Dilution formula

C₁V₁ = C₂V₂

Serial dilution

A series of dilutions that begins with a very small initial quantity of material

Total dilution factor of series dilution

The product of individual dilution factors from each step

Aliquot + formula

Measured sub-volume of original sample

• Final volume / dilution factor

Dilutant + formula

Material with which sample is diluted (ex. solvent)

• Final volume - aliquot

Dilution factor + formula

Total number of unit volumes in which your material will be dissolved

• Final concentration / initial concentration = final volume/aliquot

Precision vs. accuracy

How closely data points agree with each other vs. how close the measurements are to actual value

Pipetmen

Tools for accurately dispensing fluids