AP Bio planning on conducting scientific investigations

List the steps of the scientific method

• question collect

• Hypothesis

• Experiment

• Data

• Analyze

• Conclusion

Contrast the independent variable in a controlled experiment

Something, being manipulated

Contrast the dependent variable in a controlled experiment

Something being measured

When do you use a bar graph?

When the data is discreet (comparing groups)

When do you use a line graph?

When the data is continuous (change over time)

What are standard deviation calculations use for?

• if data is spread out

• To see what data is better

What are Standard error calculations used for?

To show how accurate your data is

What are chi-squared calculations used for?

To determine how close observed data is to expected results

When do you accept the null hypothesis in the chi square test?

If the Chi square is lower than the critical value you accept

When do you reject a null hypothesis?

If the Chi square is higher than the critical value you reject

How do you start a null hypothesis?

“ there is no significant difference between…”

What are two good scientific questions?

• includes measurable values

• Identifies the independent and dependent variable

In reality is the scientific process, linear or nonlinear

Nonlinear

While interpreting data you should?

• support a hypothesis

• Oppose a hypothesis

A good hypothesis includes what?

• A statement, not a question

• Testable

• Falsifiable

• Defines measurable variables

• Is written in the form of “if…then”

Characteristics of a true experiment include?

• Random assignment to groups

• Control of extraneous variables

• Manipulation of the independent variable

• Qualitative measurement of outcomes

• Comparison of participate groups

• Contains a control group

What are confounding variables?

Other variables that must be identified and controlled

What is quantitative data?

Numerical results

What is qualitative data?

Non-numerical results

Test groups should be a large size or…

The experiment should be performed several times

After the experiment, the results are analyzed, and a conclusion is made by?

the hypothesis is either being accepted or rejected based on the evidence

The independent variable goes on what axis

X-axis

The dependent variable goes on what axis y-axis

Is qualitative or quantitative data graphable?

Quantitative

How do you label a “good title”

By telling exactly what information the author is trying to present with the graph. (X vs Y)

Basic traits of a good graph include

• axes should be consistently numbered

• Axes should contain labels including units

• The independent variable is always shown on the X axis

• The dependent variable is always shown on the Y axis

• The line should not be extended to the origin if the data does not start there

If a line on a graph goes from solid to “broken” (dashed) this indicates what?

Shows it is a prediction

The slope of a line indicates what?

The rate at which the variables being graphed are changing

Capital (N) indicates what?

Population

Lowercase (n)indicates what?

Sample

Intervals labeled on each axes should be appropriate for?

The range of data so that most of the area of the graph can be used

The graph should have an appropriate (blank) if more than one data set is being represented

Legend

One standard deviation is what percent?

68.2%

Two standard deviations is what percent

95%

Three standard deviations is what percent

99%

What does this symbol (x̄) represent?

The mean

Mean definition

The average of given numbers calculated by dividing the sum of given numbers by the total number of numbers

Median definition

The middle number in an assorted, ascending or descending list of numbers (going from lowest to highest)

Mode definition

The value that appears most frequently in the data set

Standard error shows?

How good your data is

When error bars overlap what does that mean?

You shouldn’t trust the data (it’s not significantly significant)

When error bars do not overlap. What does that mean?

There is a statistical difference you can trust the data

How do you find the degree of freedom?

You take the number of outcomes -1

What value do you always use class?

Critical value