Lesson 15- Statistical Testing- The Sign test (When to use the sign test & calculations)

Question 1

What are the 2 types of statistics?

Answer 1

1) Descriptive statistics

2) Inferential statistics

Question 2

What are descriptive statistics?

Answer 2

Descriptive statistics- measures of central tendency & dispersion

Question 3

What are inferential statistics?

Answer 3

Inferential statistics- sample of target 🎯 population used- results are inferred for entire 🎯 population- inferential statistics used to see if results significant (null/alternate hypothesis)

Question 4

What is the level of statistical significance?

Answer 4

Level of Statistical Significance- level at which decision made to reject null hypothesis in favour for alternate (experimental) hypothesis- how sure can we be that IV having effect on DV & ✖️ by chance

Question 5

What is chance?

Answer 5

Chance- has no real cause- just happens

Question 6

What do significance levels show & what decisions can be made from them?

Answer 6

Significance levels- see if difference exists between data for control & experimental conditions
- If similar then accept null hypothesis
- BUT if real difference then accept experimental (alternate) hypothesis & reject null hypothesis

Question 7

What is probability?

Answer 7

Probability- numerical measure- determines whether results due to chance or due to real difference existing between experimental & control conditions

Question 8

What significance level is most commonly used and why is that?

Answer 8

5% level of significance (p<0.05) mainly used because:

1) ✖️ too strict or lenient- middle, fair value of significance
2) Minimises chances of making Type 1/Type 2 error (we will revisit this at A2 level)

Question 9

What does a 5% significance level mean?

Answer 9

0. 05 (5%)- shows 5% probability that results due to chance/fluke … 95% certainty that results showing real difference between control & experimental conditions
   - … if achieved then probability of results being due to chance/fluke is 5% or ⬇️ (p<0.05)

Question 10

What does 1% significance level mean & when might it be used in real life?

Answer 10

0. 01 (1%)- shows 1% probability that results due to chance/fluke … 99% certainty that results showing real difference between control & experimental conditions
   - used when research findings very important e.g. testing effect of drugs on 👨 👩 - must make sure results ✖️ due to chance BUT real difference occurs between experimental & control conditions … stricter sig level