experimental data

Question 1

the independent variable is…

Answer 1

CHANGE

Question 2

the dependent variable…

Answer 2

MEASURE

Question 3

the control variable…

Answer 3

things you keep the same

Question 4

what is reliability?

Answer 4

experiments that give the same data

Question 5

what is validity?

Answer 5

• experiments that give the same data (reliable)
• designed to be a fair test

Question 6

what is accuracy? how do you improve it?

Answer 6

results that are true
improve it by making measurements more accurate eg by using different equipment like a ruler in mm instead of cm

Question 7

what is precision?

Answer 7

the results are very similar to the mean average
eg results are 12, 14, 13 so the mean is 13 is PRECISE
results are 11, 17, 14 so the results are not

Question 8

how do you improve reliability?

Answer 8

repeat the test

Question 9

suggest some hazards of practicals:

Answer 9

• MICROORGANISMS - can be dangerous/make you ill
• FIRE eg bunsen burners
• CHEMICALS eg burning your skin, flammability
• ELECTRICITY with electrical equipment

Question 10

suggest some ways of reducing hazards

Answer 10

• wear gloves
• wear goggles
• use a heat proof mat (fire)

Question 11

sampling (eg quadrats)

Answer 11

• must be random
  (because you can’t study every organism so the sample you take must be as close to the truth as possible, therefore choosing an area that is higher than normal will disrupt the results)
  eg divide the area into a grid and then choose the coordinates out of a hat

Question 12

ethical problems in experiments

Answer 12

• treat safely/humanely eg food, water, overcrowding
  —> wild animals should be returned after the experiment to their habitat
• should gain consent from humans

Question 13

results that are abnormal are called…

Answer 13

anomalous

Question 14

discrete vs continuous data

Answer 14

discrete - set groups of data eg shoe size or the number of siblings (because you can’t have half a person)
continuous - numerical data that can be any value (2.5 or 7453765) eg length or temperature

Question 15

qualitative vs quantitive data

Answer 15

qualitative - in words eg favourite colour
quantitative - uses numbers

Question 16

correlation types

Answer 16

• positive
• negative
• no correlation

Question 17

why do correlation exist?

Answer 17

• chance
• caused by an unseen variable
• cause each other

Question 18

what is an evaluation?

Answer 18

a analysis of the practical eg
- what can be improved?
- was it a fair test?
- were there any anomalous results? if not, mention this
- was it precise, reliable, accurate, etc.

Question 19

graphwork - dependent

Answer 19

Y axis
(family)

Question 20

independent - graphwork

Answer 20

x axis
(ex)