Experimental Design Flashcards
10 Science. Unit 1. 2023
What is valid data?
For data to be valid the experiment must have:
- 1 independent variable
- 1 dependant variable
- All other variables controlled
Define accuracy and precision.
Accuracy is how close the result is to the true or accepted value.
Precision is how similarly the results are with each other.
Experimental uncertainty.
Experimental uncertainty exists for any data that is measured.
Experimental uncertainty may be in the form of random or systematic error.
What is Random error?
Random error:
- Is always present and unpredictable.
- Affects the precision of measurements.
- Occurs due to mis-reading, guessing or delayed reaction to data.
- Can be minimised by calculating an average.
What is Systematic error?
Systematic error:
- Is caused by faulty equipment or operator errors.
- Affects the accuracy of results.
- Occurs when equipment is incorrectly calibrated or operator inability to use equipment properly.
- Cannot be minimised.
Identify the International System of units, SI units.
- distance - metres (m)
- mass - kilograms (kg)
- force - Newtons (N)
- time - seconds (s)
- energy - joules (J)
Identify the basic unit conversions.
- nano (n) 10^-9
- micro (µ) 10^-6
- milli (m) 10^-3
- kilo (k) 10^3
- Mega (M) 10^6
- Giga (G) 10^9
- Tera (T) 10^12
Identify the three experimental variables.
Independent variable: the variable that is changed.
Dependant variable: the variable that is measured, affected by changes to the independent variable.
Control variables: variables that remain constant.
Define a hypothesis and provide an example.
A hypothesis is a proposed relationship between the variables in a scientific investigation.
If IV, then DV.
If plants are exposed to UV light, then their growth will be inhibited compared to plants not exposed to UV light.
Define qualitative data and provide an example.
Qualitative data is data based on observations that are described.
For example, a red car.
Define Quantitative data and provide an example.
Quantitative data uses numerical quantities or amounts.
For example, 12 cars.
Identify the two types of quantitative data and provide an example.
Discrete data: collected by individually counting whole numbers.
Eg. there are 50 people in a room.
Continuous data: data that is measured and can always be divided into smaller measurements given more suitable equipment.
Eg. a persons height is 1.8 metres.
Describe what type of data a pie chart is used for.
A pie chart is used for:
- qualitative or
- quantitative discrete data
Used to express data as a percentage or proportion of a whole.
Describe what type of data a column/bar graph is used for.
A bar graph is used for:
- qualitative or
- quantitative discrete data
Used to compare data across categories.
Describe what type of data a XY/scatter plot graph is used for.
An XY scatter plot is used for:
- quantitative continuous data
Used to illustrate a relationship between two variables.
