Error analysis, uncertainties, graphs, evaluating and concluding

Question 1

How can the trend of a graph be represented?

Answer 1

A line of best fit

Question 2

State the 3 types of correlation and what they mean

Answer 2

• Positive correlation: As one variable increases, the other increases
• Negative correlation: As one variable increases, the other decreases
• No correlation: There is no relationship between the variables

Question 3

When is a line of best fit curved?

Answer 3

When there is a non-linear relationship between variables

Question 4

What is a prediction?

Answer 4

A specific testable statement about what will happen in the experiment

Question 5

What is a hypothesis?

Answer 5

A suggested explanation for a fact or observation

Question 6

What is a variable?

Answer 6

A quantity which has a potential to change

Question 7

What is an independent variable?

Answer 7

A quantity that can be changed in an experiment

Question 8

What is a dependent variable?

Answer 8

A quantity that is measured in an experiment

Question 9

What is a control variable?

Answer 9

A quantity which is kept the same in an experiment

Question 10

What is discrete data?

Answer 10

Data that can only take certain values

Question 11

What is continuous data?

Answer 11

Data that can have any value on a scale

Question 12

What is categoric data?

Answer 12

Data that can be sorted into categories

Question 13

What is ordered data?

Answer 13

Categoric data where the categories can be put into order

Question 14

State the 2 types of errors

Answer 14

• Random error
• Systematic error

Question 15

What is random error?

Answer 15

An error produced by uncontrollable variables

Question 16

What is systematic error?

Answer 16

An error produced by experiment apparatus or method

Question 17

Define calibration

Answer 17

Checking a scale by measuring a known value

Question 18

What are zero errors?

Answer 18

Measuring instruments falsely reads a non-zero value when the true value being measured is zero

Question 19

Define uncertainty

Answer 19

An interval in which the true value of a measurement is likely to lie

Question 20

Define absolute uncertainty

Answer 20

The uncertainty of a measurement given as a certain fixed quantity

Question 21

Other than absolute uncertainty, how can uncertainty be represented?

Answer 21

• Fractional uncertainty
• Percentage uncertainty

Question 22

State the equation for fractional uncertainty

Answer 22

Fractional uncertainty = uncertainty/measurement

Question 23

State the equation for percentage uncertainty

Answer 23

Percentage uncertainty = Fractional uncertainty x 100

Question 24

What happens to the uncertainty when adding or subtracting data?

Answer 24

The absolute uncertainties are added together

Question 25

What happens to the uncertainty when multiplying or dividing data?

Answer 25

The percentage uncertainties are added together

Question 26

What happens to the uncertainty when the data is raised to a power?

Answer 26

The percentage uncertainty is multiplied by that power

Question 27

How can uncertainty be reduced?

Answer 27

- By doing repeats of the method and finding an average - By using appropriate equipment, i.e computers or data loggers to measure smaller intervals

Question 28

How is uncertainty represented in a graph?

Answer 28

By error bars

Question 29

What are worst lines?

Answer 29

Lines of best fit which have the maximum gradient, going through all error bars

Question 30

How is the uncertainty of a gradient calculated?

Answer 30

By calculating the worst gradient and best gradient using the error bars and finding the difference between them

Question 31

How are precise results represented?

Answer 31

By having a smaller amount of spread of data from the mean

Question 32

What is precision dependent on?

Answer 32

The amount of random error in readings

Question 33

How are repeatable results represented?

Answer 33

If an experiment can be repeated and the same results achieved

Question 34

How are reproducible results represented?

Answer 34

If someone else can recreate your experiment with the same equipment or methods and achieve the same results

Question 35

How can results be valid?

Answer 35

By keeping all the variables apart from the one being tested constant

Question 36

How can results be accurate?

Answer 36

If the result achieved is really close to the true answer

Question 37

For a conclusion to be valid, what must it include?

Answer 37

Evidence, valid data arising from the experiment

Question 38

Define resolution

Answer 38

The smallest change in a quantity that causes a visible change in the reading recorded by the measuring instrument

Question 39

How can a value be represented as measured to a higher resolution?

Answer 39

By having a higher number of significant figures

Question 40

What is a reading?

Answer 40

A single value

Question 41

What is a measurement?

Answer 41

A combination of readings

Question 42

What is the absolute uncertainty for a reading?

Answer 42

Half the smallest division

Question 43

What is the absolute uncertainty for a measurement?

Answer 43

Atleast ± the smallest division

Question 44

State the 6 SI base quantities and their units

Answer 44

- Mass(kilograms/kg) - Length(metre/m) - Time(second/s) - Current(Ampere/A) - Temperature(Kelvin/K) - Amount Of Substance(Mole/mol)