Research methods: statistical analysis

Question 1

How can the degree of variability be calculated?

Answer 1

Standard deviation

Question 2

what is it possible to do with normally distributed results?

Answer 2

estimate the % of all values within a particular range around the mean

Question 3

what do most scientific investigations produce?

Answer 3

quantitative results that are compared to establish the significance of any differences

Question 4

what will a good scientific analysis do?

Answer 4

Prove as there is always something remaining to find (more to be investigated)

Question 5

what is the key issues with when deciding the significance of a conclusion?

Answer 5

the level of confidence

Question 6

what makes a result statistically significant?

Answer 6

if the result is unlikely to have occurred by random chance

Question 7

what can be done with the random chance in investigations?

Answer 7

it can be calculated
the lower the value the greater the reliability of the result

Question 8

what is the p-value? (probability)

Answer 8

the probability of an event being caused by random chance

Question 9

how is the p-value usually expressed?

Answer 9

the probability that a single event was significant
0.9,0.95,0.99,0.995
as a degree of confidence that the difference being investigated is significant

Question 10

does showing significance mean importance?

Answer 10

does not mean it is important or that a casual relationship has been found
2 correlated factors may be caused by a variable that hasnt been investigated

Question 11

what are the comparisons between p-value and significance level?

Answer 11

0.1= 90%
0.05= 95%
0.01=99%
0.005=99.5%

Question 12

when is spearman’s rank used?

Answer 12

used to see whether there is a consistent change in the value of one variable as another variable increases or decreases

Question 13

what does spearman rank assess?

Answer 13

how closely 2 variables are correlated

Question 14

what are some examples of where spearman rank can be used?

Answer 14

crop yield increases as fertiliser application increases
noise levels decrease as distance from road increases
number of moths increase as temperature rises

Question 15

what is the chi square test used for?

Answer 15

compare the frequencies or numbers of things in different groups are significantly different

Question 16

when can chi square not be used?

Answer 16

data that can be continuously variable such as ,measured or calculated

Question 17

what is an example of a hypothesis used for the chi squared test? (Wood mice)

Answer 17

different management practices in a range of woodlands affects the number of dormice

Question 18

when is the T-test used?

Answer 18

if there is a significant difference between two means where data was measured

Question 19

what are some examples of data used in the T-test?

Answer 19

mass
length
wind speed
dissolved oxygen level

Question 20

when would you use Mann Whitney u over t-test?

Answer 20

if the data isn’t normally distributed

Question 21

what are some examples of hypothesis that can be tested using T-test?

Answer 21

mean mass of lobsters is higher in areas where collection is banned
dissolved oxygen level is lower in a sewage polluted river
wind speed is lower in a woodland than in a clearing

Question 22

when is the Mann Whitney U used?

Answer 22

used when there is a significant difference between 2 median values where the data was counted

Question 23

what is an example of where the Mann Whitney U can be used?

Answer 23

fewer cars use a road when road charging is introduced
biodiversity is higher in a hedge that is trimmed less frequently
fewer seeds germinate at pH5 then pH7