Revision

Question 1

What is the hypothetico-deductive method?

Answer 1

proposed discription of the scientific method.

Question 2

What are the key steps of the hypothetico-deductive method?

Answer 2

1. Observation
2. Model
3. Hypothesis
4. Experiment
5. Result reporting

Question 3

Why is it usefull to establish an alternate and null hypothesis before you experiment?

Answer 3

Null hypothesis - know what you will reject or accept
Idicates the question or direction effect if we can reject our null hypothesis we can accept an alternative one. t-tests and tail tests.

Question 4

What is an independant variable?

Answer 4

The variable that you control and manipulate.

Question 5

What is the dependant variable?

Answer 5

The variable that you measure.

Question 6

What is the confidence interval?

Answer 6

95% confidence level in the middle in two tailed tests.

way to express the precision of the estimate of the population.

Question 7

How do we reliably estimate population parameters?

Answer 7

Randomisations - avoiding bias
Replication - more reliable and allows repetition
Control - shows what we are measuring is what actually is being changed.

Question 8

What is central tendency?

Answer 8

summary to measure a whole set of

Question 9

What do we use to measure the central tendency of parametric data?

Answer 9

The mean

Question 10

What do we use to measure the central tendency of non-parametric data?

Answer 10

Mode and median

Question 11

Why is a normal distribution advantageous?

Question 12

What is the central limit theorem?

Question 13

What 4 things affect the power of statistical tests?

Answer 13

1. Sample size
2. variability of data
3. magnitude of the difference between sample means
4. Type 1 error probability

Question 14

What is a type 1 error?

Answer 14

False positive - rejecting the null hypotheses

Question 15

What is a type 2 error?

Answer 15

False negative - accepting the null hypotheses

Question 16

comparing 2 independant samples?

Samples

Answer 16

for parametric data = t-test
for non-parametric data = mann-Whitney U-test

Question 17

comparing 2 non-independant samples?

Paired samples

Answer 17

for parametric data = paired t-test
for non-parametric data = Wilcoxon text

Question 18

One tailed test

Answer 18

H0- No difference between the two groups.
HA- Mean on one group is larger or smaller than the other.

Question 19

Two tailed test

Answer 19

H0- No difference between the two groups.
HA- Mean of one group is different to the other group

Question 20

What are the 4 assumptions of the t-test?

Answer 20

1. follow continuous or ordinal distribution
2. Smaples are independant of eachother
3. follow normal distribution
4. variance is the same

Question 21

What is the Levene’s test?

Answer 21

Test for equal variance
before the independant t-test
p>0.05 - equal
p<0.05 - unequal