Unit 1 Flashcards
What is inquiry?
search for information and explanation
What are the two steps of inquiry?
1) making observations
2) forming hypothesis
What is data?
recorded observations
What does qualitative observations mean?
observations with senses
What does quantitative observations mean?
observations measured using instruments
What is inductive reasoning?
derive generalizations based on a large number of specific observations
What is a hypothesis?
predictions that can be tested by recording more observations or experiments
- an explanation to a question
- tested by an experiment or continued observation
- can be disproven, but cannot be proven true
What is deductive reasoning?
specific results are derived from general premisis
What is a null hypothesis?
a hypothesis which the researcher tries to disprove, reject, or nullify
(a hypothesis that there will be no difference between two groups of data, and the experimental observations are due to chance)
What is a theory?
- summarizes a group of hypothesis
- broader in scope
- new hypothesis can be generated from it
- supported by massive body of evidence
- never becomes a law
What is a scientific law?
- statement of fact usually a mathematical formula
- describes an observation (not “how” or “why”)
- generally accepted to be true + universal
- basis for scientific method
What does an experiment start with?
an observation and hypothesis
What are the two groups used in an experiment?
control groups and experimental groups
What is a variable?
something that is changed in the experiment
What is a constant?
something that does not change throughout the experiment
What is an independent variable?
the one factor that is changed by the person doing the experiment; represents a quantity that is being manipulated in the experiment
What is a dependent variable?
the factor which is measured in an experiment; represents a quantity whose value depends on how the independent variable is manipulated
What do control groups help eliminate?
experimental error and biases of researchers
Why is statistical analysis necessary?
to help determine whether or not data is significant and reliability of the experiment increases
T or F : controls are constants
false
What are the two types of controls?
positive and negative
What are positive controls?
groups that are not exposed to experimental treatment or independent variable, but is exposed to a treatment known to produce the expected effect
What do positive controls ensure?
that there is an effect when there should be an effect
What are negative controls?
groups that are not exposed to any treatment or exposed to a treatment that is known to have no effect ; group where nothing is expected to happen
What do negative controls ensure?
that there is no effect when there should be no effect ; that no cofounding/outside variable has affected the results, or to factor in any likely sources of bias
T or F : experiments do not need to contain both a positive and negative control
true
When do scientists use positive controls?
when they are trying to induce a positive result
How do descriptive statistic help researchers?
helps to describe and quantify differences between data sets
What is the mean?
the average of the data set
How do you find the mean of a data set?
sum all the data points in the data set and then divide this number by the total number of data points
What is the median?
the middle number in a range of data points
How do you find the median of a data set?
arrange the data points in numerical order then find the middle number , and if there is an even number of data points, average the two middle numbers
What is variability?
the measure of how far a data set diverges from the central tendency ( how spread out the data points are)
What is range?
the difference between the largest and smallest values
What does a larger range indicate?
a greater spread of data and greater variability
What does a smaller range indicate?
a smaller spread of data and less variability
What is standard deviation?
a measure of how spread out the data is from the mean
What does low standard deviation indicate?
the data is closer to the mean (the independent variable is likely causing changes)
What does high standard deviation indicate?
the data is farther from the mean (spread out) ; factors other than the independent variable are likely causing changes
What are the four steps to solve for standard deviation?
1) find the mean
2) determine the deviation from the mean for each data point and square it
3) calculate the degrees of freedom (n-1), n is the number of data values
4) put it all together to calculate for S
What is standard error the mean used for?
to determine the precision of and confidence in the mean value
What is standard error of the mean based on?
- standard deviation (variability)
- the number of data point
What does a low standard error indicate?
higher confidence in the mean value
What does it mean if error bars overlap?
the difference is not significant
What does it mean if error bars do not overlap?
the difference may be significant
