Lab 1: Introduction to Science and Scientific Method

Hypothesis

A proposed explanation made on the basis of limited evidence as a starting point for further investigation.

Prediction

The expected outcome of an experiment if the hypothesis is true.

Experiment

A controlled scientific procedure designed based on a prediction.

Theory

A hypothesis that has not been refuted despite extensive experimentation and/or observation.

Deductive Reasoning

A logical process that begins with a general premise and leads to a specific conclusion based on reasoning and evidence. Deductive conclusions are reliable provided the premises are true.

Ex: All spiders have eight legs. A tarantula is a spider. Therefore, tarantulas have eight legs.

Inductive Reasoning

A logical process that extracts a likely premise from specific and limited observations.

Ex: I tend to catch colds when people around me are sick. Hypothesis: Colds are contagious.

Natural Events

Occurrences in nature that are observed and lead to questions about their causes.

Falsification

The process of discarding or modifying a hypothesis based on experimental results.

Scientific Method

A process that starts with a general statement or hypothesis and examines possibilities to reach a specific, logical conclusion.

Evidence

Observations, measurements, and experimentation that support a scientific theory.

Objective Explanations

Explanations of nature that are not influenced by personal beliefs or biases.

Experiments and Observations

Methods used to test hypotheses and gather evidence in science.

Premise

A statement that is assumed to be true and serves as the basis for reasoning.

Syllogism

A form of deductive reasoning consisting of a major premise and a minor premise that together reach a logical conclusion.

Major Premise

The first statement in a syllogism that provides a general principle.

Minor Premise

The second statement in a syllogism that applies the major premise to a specific case.

Conclusion

The logical outcome derived from the premises in deductive reasoning.

Controlled Experiments

Experiments designed to evaluate a hypothesis by isolating variables and observing outcomes.

Reliability of Deductive Conclusions

Deductive conclusions are reliable provided the premises are true.

Validity of Arguments

An argument is valid if the conclusion logically follows from the premises, regardless of the truth of the premises.

Truth in Inductive Reasoning

Inductive reasoning does not guarantee that the conclusion will be true, even if all observations are correct.

Interplay in Science

The constant interaction between inductive inference and deductive inference in the scientific method.

Generalization

A broad statement or conclusion drawn from specific instances or observations.

Pattern Recognition

The process of identifying trends or regularities in data, which is crucial for inductive reasoning.

Control Group

A group of test subjects that receives a placebo injection in an experimental study.

Experimental Group

A group of test subjects that receives the treatment or variable being tested.

Double-Blind Study

A study in which neither the test subjects nor the technicians know which members are part of the treatment or control group.

Dependent Variable

The response being measured in an experiment, such as the efficacy or safety of a vaccine.

Independent Variable

The variable that is manipulated in an experiment, such as membership in the control or treatment groups.

X-axis

The horizontal axis in a graph that typically represents the independent variable.

Y-axis

The vertical axis in a graph that typically represents the dependent variable.

Probability

A measure of the likelihood that an event will occur, calculated as event / all possible outcomes.

Law of Multiplication

The principle that the probability of two mutually exclusive events both occurring is the product of their individual probabilities.

Law of Addition

The principle that the probabilities of all mutually exclusive events must sum to 1 (100%) of all outcomes.

Null Hypothesis (Ho)

The hypothesis that states astrology cannot make a correct prediction any better than random chance.

Alternative Hypothesis (H1)

The hypothesis that states astrologists' claims are valid and predictions are more accurate than random chance.

Random Match Probability

The probability of a random match between an astrological prediction and its correct sign, calculated as 1/12 or 8.3%.

Chi-Square Test

A statistical test used to determine if the measured response is significantly different from the expected outcome under the null hypothesis.

Chi-Square Formula

C2 = S[(observed - expected)^2 / expected]

Used to calculate the Chi-square value.

Critical Value

A threshold value (3.84 at alpha = 0.05) used to determine whether to reject the null hypothesis.

Reject Ho

The conclusion drawn when the Chi-square value is greater than the critical value, indicating support for the predictive powers of astrology.

Continuous data

Data that can take any value within a range, such as height or weight, and may require fractions or decimals.

Discontinuous data

Data that consists of whole counts, such as the number of individuals in a population.

Progress graph

A graph that displays changes in the dependent variable over time.

Interpolation

Estimating a value within the range of measured data points.

Extrapolation

Estimating a value beyond the range of measured data points, assuming the relationship holds constant.

Frequency distribution graph (Histogram)

A graph that represents the frequency of data points within specified intervals.

Scatter plot diagram

A graph used to determine if a relationship exists between two variables.

Positive correlation

A relationship where two variables increase or decrease in parallel, resulting in a positive slope.

Negative correlation

A relationship where one variable increases while the other decreases, resulting in a negative slope.

R² value

A statistical measure that represents the proportion of variance for a dependent variable that's explained by an independent variable.

Histogram

A graphical representation of the distribution of numerical data using bars to show frequency. Histograms only need to show y gridlines.

Gridline Density

Computer-generated graphs should show an appropriate density of gridlines, with the option to show major and minor gridlines in Excel.

Graph Clarity

Graphs should not appear too 'busy' with too many gridlines.

Axes Labeling

Axes on graphs should be labeled with category and the units in which that category is measured.

Interval Consistency

Intervals on x and y axis should represent the same magnitude of increase.

XY Scatter Diagram

Using the XY Scatter diagram function in Excel gives more control over the x and y axes compared to the Line Graph function.

Graph Background

The background for graphs should be white to save toner or ink.

Setting Background in Excel

To set the background to 'none', double click on any space on the graph between gridlines and adjust the settings in the dialog box.

Axis Value Range

Set the maximum and minimum values of each axis to extend only a little beyond the range of your data or to coincide with your maximum/minimum data values.

Maximum Y Axis Value

If the largest y value in your data is 78, then set the maximum value of the y axis to 80.

Maximum X Axis Value

If the largest x value in your data set is 24, then set the maximum value of the x axis to 25.

y gridline intervals

The intervals on the y-axis of a graph, which in this example are in units of 5.

default origin in Excel

The standard starting point for graphs in Excel, which is the coordinate (0, 0).

legend in graphs

A key that explains the meaning of different curves or plots in a graph, required for graphs with more than two curves.

font size for titles

The recommended size for titles in graphs, which should not exceed 12 point.

font size for axes labels

The recommended size for axes labels in graphs, which should be no more than 10 or 8 point.