Experiments and variables

Question 1

whats a hypothesis

Answer 1

A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with the available scientific theories.

Question 2

what is an independent variable

Answer 2

the variable we choose to see what happens

Question 3

what is a dependent variable

Answer 3

the variable we measure

Question 4

what is a continuous variable

Answer 4

(e.g time or mass) can have an numerical value. A continuous variable is one that can assume different values between each point. Put as an example (e.g when looking at height) one can assume a height of 178, 178.1, 178.2. . . 178.9. Thus continuous variables can be used when looking at time or length for example.

Question 5

what is an ordered variable

Answer 5

an ordered variable (e.g small, medium or large) can be listed in order

Question 6

what is a discrete variable

Answer 6

a discrete variable can have any value that is a whole number

Question 7

what is a categoric variable

Answer 7

its a variable that can be labelled e.g red, blue

Question 8

when is a line graph used

Answer 8

used to present data where the independent variable and the dependent variable are both continuous. A line of best fit can be used to show the relationship between variables

Question 9

when is a bar graph used

Answer 9

used to present data when the independent variable is categoric and the dependent variable is continuous

Question 10

in a fair test the only factor that should affect the dependent variable is the independent variable. Control groups are used to make sure observed results are due to changes in the independent variable only.
name the three links between variables that a scientist would look for.

Answer 10

casual - a change in one variable produces a change in the other variable
a “chance” occurrence
due to an “association” where both of the observed variables are linked to a third variable.

Question 11

suggest ways results could be made more reliable

Answer 11

secondary sources - looking at data from secondary sources
using an alternative method
peer review - a process where a qualified professionals check an individuals work

Question 12

whats an anomalous value

Answer 12

is a value that is outside the current pattern

Question 13

when coming to a conclusion what factors are taken into account

Answer 13

accuracy
precision
reliability
validity