How science works

Question 1

Difference between continuous and discontinuous data

Answer 1

Continuous: data that falls into discrete categories (bar charts) e.g eye colour
Discontinuous: Data that does not fall into discrete categories (line graphs) e.g temperature

Question 2

What is normal distribution

Answer 2

A bell shaped graph. Most results in the middle and tapers off towards either extreme

Question 3

Mean, median and mode

Answer 3

Mean: the readings all added together and divided by the number of readings
Median: middle value in results in rank order
Mode: most frequently occurring value

Question 4

What is standard deviation

Answer 4

A measure of spread of results around the mean.
The greater the standard deviation, the less reliable the results are.

Question 5

Why is standard deviation more useful than range?

Answer 5

Takes into account all the data, not just the extremes so is less influenced by outliers.
Tells us how spread out the result is around the mean
Used in statistical tests to tel us if there is a significant difference between the two sets of data

Question 6

What do SD error bars tell us

Answer 6

If error bars overlap, the difference between two sets of data is not significant and is due to chance and vice versa

Question 7

What is uncertainty?

Answer 7

The interval within the true value is expected to lie, with a given level of confidence of probability

Question 8

What is percentage error?

Answer 8

The difference between approximate and exact values as a percentage

Question 9

What does reliable mean?

Answer 9

The results can be consistently reproduced in independent experiments

Question 10

What does repeatable mean?

Answer 10

If the experiment is repeated and the same results are obtained

Question 11

What does reproducible mean?

Answer 11

If the experiment is repeated by someone else and the same results are obtained

Question 12

What is the difference between monitoring and controlling a variable?

Answer 12

Monitoring is taking readings of a variable during an investigation. Controlling is keeping a variable at a predetermined or set level during an experiment.

Question 13

What is the difference between outliers and anomalies?

Answer 13

Anomalies are values not judged to be part of the variation caused by random uncertainty, whilst outliers are the most extreme parts of the variation, but are real results.

Question 14

Correlations

Answer 14

Shows that there is a relationship between 2 variables, but may not be a causal one.

Question 15

Causal links

Answer 15

A change in one variable causing the change in another

Question 16

What are double blind trials

Answer 16

When the volunteers and scientists both do not know which groups are taking the new drugs
Ensure results not influenced by bias in symptom reporting, personal interests and physiological effects in volunteers.

Question 17

Why do we allocate patients randomly in trials

Answer 17

To remove human bias

Question 18

Placebos

Answer 18

Pills without the active ingredient, so we know the ingredient causes any measured changes.

Question 19

What are risk factors

Answer 19

Something that increases the chance of getting a disease

Question 20

Peer review

Answer 20

When other scientists repeat the experiment to see if they get the same results. Makes sure experiments were well carried out and results have been interpreted reasonably.