unit 1: chemistry of life

topic 0: biology review and an intro to statistics

Hypothesis

A testable explanation or prediction for an observed phenomenon

Null Hypothesis (\(H_{0}\))

A statement that the independent variable has no effect or no difference on the dependent variable.

Alternative Hypothesis (\(H_{a}\))

does have an effect or difference on the dependent variable.

Control Group

A baseline group in an experiment that does not receive the new treatment.

Negative Control

A group where no change or effect is expected (treatment is omitted entirely).

Positive Control

• A group exposed to a treatment already known to produce an effect, used to check if the experiment is working properly.

Experimental Group:

The group that receives the specific treatment or manipulation being tested

Independent Variable:

The variable that the researcher deliberately changes or manipulates (graphed on the x-axis

Dependent Variable

: The variable that is measured or counted as a response (graphed on the y-axis

Constants

: All the conditions and factors that are kept identical across all experimental groups to ensure a fair test..

Statistics

The mathematical science of collecting, analyzing, presenting, and interpreting data.

Descriptive Statistics

Calculations that summarize the main features of a data set (like average or spread).

Inferential Statistics:

• Methods used to draw conclusions or make predictions about a larger population based on a sample of data.

Central Tendencies

Single values that represent the center or typical value of a data set.

Mean

The arithmetic average of all data points.

Median

The middle value when all data points are ordered from least to greatest.

Mode:

appears most frequently in a set.

Variability

A measure of how spread out or scattered the data points are from the center.

Range

The difference between the highest and lowest values in a data set.

Standard Deviation:

A statistic that shows how much individual data points deviate from the mean.

Standard Error (\(SE\)

A value that estimates how far the sample mean is likely to be from the true population mean, calculated as SD/ square root of sample size.

Chi-Square (\(\chi ^{2}\)) Test

: A statistical formula used to compare observed results with expected results to see if any deviation is due to random chance or a real factor