Genetics Lab: Chi-Square Test and Critical Calculations

Vocabulary flashcards covering key terms related to Chi-Square tests, scientific calculations, and pipetting techniques from the lecture notes.

Chi-Square (X2)

A statistical test used to determine whether a given set of data approximates theoretically expected ratios.

Chi-Square Test

A statistical test used to determine how well the observed phenotypic ratios match the expected phenotypic ratios given a hypothesized pattern of inheritance.

Observed Data

The real-life outcomes or results obtained from an experiment.

Expected Data

The mathematical or calculated outcomes predicted based on a sound theoretical foundation in genetics research.

Null Hypothesis (H0)

States that the difference between observed and expected distributions is not significant, and any difference is due to random chance.

Critical Chi-Square (critical ext{ extchi}2)

A value found in a Chi-Square table, used as a threshold to determine whether to reject or fail to reject the null hypothesis.

Fail to reject the null hypothesis

Occurs when the calculated ext{ extchi}2 is less than or equal to the critical ext{ extchi}2, interpreted as there being no significant difference between the two groups.

Alternative Hypothesis (HA)

States that the difference between observed and expected distributions is significant and not due to chance alone.

Reject the null hypothesis

Occurs when the calculated ext{ extchi}2 is greater than or equal to the critical ext{ extchi}2, interpreted as there being a significant difference between the two groups.

Degrees of Freedom (df)

Calculated as the number of phenotypes minus 1 (# Phenotypes 1).

P-Value (0.05)

A statistical measure representing the probability of obtaining observed results if the null hypothesis were true; commonly set at 0.05, allowing for 5% error in accepting a hypothesis that should really be rejected.

95% Confidence

The level of certainty in "failing to reject" the null hypothesis, often associated with a p-value of 0.05.

Critical Value (X2 P-Value)

The value obtained at the intersection of the p-value and degrees of freedom in a Chi-Square table, representing the limitation at which the null hypothesis is rejected.

Sigma Symbol ( ext{ extSigma})

Represents the sum of what follows in a mathematical formula.

Metric System

The universal standard for units of measurement within the scientific community, based on the power of 10s.

Dimensional Analysis

A method of converting between units, using known proportions or ratios (conversion factors) to result in a different unit or dimension.

Conversion Factors

Ratios of related physical quantities expressed in desired units, used in dimensional analysis.

Order of Magnitude

The relative size of a number, referring to the power of 10 that can be factored out, often used for comparison between two numbers.

Scientific Notation

A method scientists use to handle very large or very small numbers, expressed as a coefficient multiplied by a base (10) raised to an exponent.

Coefficient (in scientific notation)

The number part in scientific notation (e.g., 5.6 in 5.6 x 10^-9).

Exponent (in scientific notation)

The power to which the base (10) is raised in scientific notation, indicating the number of places the decimal point is shifted.

Significant Figures (Sig Figs)

The digits in a number that contain meaningful information about its value, excluding its order of magnitude.

Mole (mol.)

A unit representing 6.022 x 10^23 particles (molecules) of a substance, with a mass equal to its molecular weight in grams.

Molar (M)

An adjective describing the concentration of a solution in moles per liter (mol/L).

Molarity

The moles of solute per liter of solvent in a solution (mol/L).

Simple Dilution formula (C1V1=C2V2)

A formula used to calculate dilutions, where C1 is the stock solution concentration, V1 is the stock solution volume, C2 is the final solution concentration, and V2 is the final solution volume.

Stock Solution

A concentrated solution that will be diluted for use.

Final Solution

The diluted solution after adding solvent to the stock solution.

Serial Dilution

A process of conducting a series of simple dilutions, where the diluted material from a previous step becomes the source for the next, amplifying the dilution factor quickly.

Aliquot

A measured sub-volume of the original sample, calculated as Final Volume / Dilution Factor.

Dilutant

The material (solvent/diluent) used to dilute a sample, calculated as Final Volume Aliquot.

Dilution Factor

The total number of unit volumes in which a material will be dissolved, calculated as Final Concentration/Initial Concentration or Final Volume/Aliquot.

Uncertainty

A specified range of values within which scientists expect the "true value" of a measurement or calculated quantity to fall, often expressed as (best estimate uncertainty).

Precision

A measure of how closely data agree with each other or how tightly they cluster together.

Accuracy

How close measurements, or their mean, are to the actual (true) value.

Pipetmen (Micropipetmen)

Precision instruments used for accurately measuring and dispensing small volumes of fluid in scientific experimental procedures.