Lesson 1.3

Question 1

What is an independent variable?

Answer 1

The variable that is being changed or manipulated.

Question 2

What is a dependent variable?

Answer 2

The variable that is responding or the effect caused by independent variable.

Question 3

What axis’s do the independent and dependent variables go on?

Answer 3

The independent variable goes on the x -axis while the dependent goes on the y-axis.

Question 4

What is a hypothesis?

Answer 4

An educated guess about what will happen in you experiment.

Question 5

What are the two steps to writing a hypothesis?

Answer 5

Step 1 - Come up with a specific reason that explains the phenomenon
The <phenomenon,topic> is (due to/caused by) ,specific reason>
Step 2 - Write a testable statement; actual hypothesis
If <independent> is (increased or decreased) then, <dependent> will (increase or decrease).</dependent></independent>

Question 6

What is a control group?

Answer 6

The standard to which comparisons are made in an experiment.

Question 7

Why do we need a control group?

Answer 7

To be able to identify and observe the changes that occurred in the experimental group/s based on the independent variable.

Question 8

How many control groups and experimental groups can you have?

Answer 8

• Only one control group
• Can have one or more experimental group/s

Question 9

Why shouldn’t you use more than one independent variable?

Answer 9

So you can interpret your results better because multiple independent variables will make it hard to observe certain changes and data.

Question 10

What is a line graph and when should it be used?

Answer 10

Graph used to show change over time and should be used if independent variable is quantitative or related to time.

Question 11

What is a bar graph and when should It be used?

Answer 11

Graph used to show grouped independent variables; should be used when independent variables are grouped (categorical).

Question 12

What are error bars?

Answer 12

Gives an idea of variability within a sample and tells us the level of uncertainty in our experiment.

Question 13

How can we analyze errors bars?

Answer 13

If error bars on a graph cross/overlap then there isn’t a significant difference or there is no difference at all. If error bars don’t overlap/cross then there is a difference between them.

Question 14

What are confidence intervals and standard errors?

Answer 14

Confidence intervals state that no overlap means difference while standard errors show that overlap means difference.

Question 15

What do short error bars and long error bars mean?

Answer 15

Short errors bars show that data is more reliable while long error bars show that there is more uncertainty in data.