Paper 1 PAG Q

Question 1

Explain why standard deviation is a better measurement than the range ?

Answer 1

• Less affected by an outlier
• The standard deviation considers every value in the data

Question 1

How to design an investigation / experiment ?

Answer 1

• Name independent variable
• Name dependant variable
• Name controlled variables / conditions that remain constant
• Use a control to increase validity of control
• Determine a method for assessing dependant variable
• Use large sample size to reduce effect of anomalies
• Repeat experiment multiple times to identify and eliminate anomalies

Question 2

When using animals, what should be included when devising an experiment ?

Answer 2

• Different species of animal should be used
• Ethical concerns should be considered ( eg. chickens should be reared in humane conditions )
• Consideration of negative effects on animals ( eg. Large muscle mass in chickens may limit their movement )

Question 3

What should be considered/ remain constant when measuring glucose concentration of diabetic patients ?

Answer 3

• Age of patient
• Sex of patient
• Type of diabetes patient suffers from
• Blood glucose being measured using the same method
• Blood glucose being measured the same time of day / after eating

Question 5

How to improve an experiment/ validity of conclusion ?

Answer 5

• Increase the sample size
• Repeat the experiment three times, identify and discard any anomalies and calculate mean
• Calculate range / standard deviation
• Add bars to graph
• Peform statistical test

Question 6

Why should you repeat experiment three times ?

Answer 6

• Reduce impact of anomalies
• Ensure/ measure repeatability
• Allow calculation of standard deviation/ statistical test
• Calculate demean more likely to be accurate/ closer to actual value than individual values

Question 7

Why calculate the standard deviation ?

Answer 7

• Measure variability of results
• Standard deviation is less affected by anomalous results