Session 5: Statistical testing

Question 1

inferential statistics

Answer 1

drawing conclusions about a population based on sample data

- we formulate hypotheses using a sample drawn from the population

Question 2

Sampling error

Answer 2

random variability in a statistic from sample to sample

- bc. they sample statistics are not perfect estimated of their corresponding population parameter

Question 3

Nulll hypothesis tetsing

Answer 3

formal approach to decicidng whther a statistical relationship in a sample reflects a real relationship in the population ot is just due to chance

Question 4

What is a research hypothesis?

Answer 4

claims a more or less precise relationship between two or more variales that is expected to holf for a given population

Question 5

Research hypothesis can be classified into..

Answer 5

1. Hypothesis about differences
2. Hypothesis about correlations
3. HYpothesis about changes

Question 6

The logic of null hypothesis testing

How likely the sample result would be if the null hypothesis were true?

Answer 6

• if the sample result would be extremely unliekly if the null hypothesis were true then we reject the null hypothesis in favor of the alternative hypothesis
• if the sample result would not be extremely unlikely if the null hypothesis were true, then we retain the null hypothesis

Question 7

p- value (and it’s meaning)

Answer 7

probability of the sample result or a more extreme result if the null hypothesis were true

• low p-value: the sample result would be unlikely if the null hypothesis were true, rejection of the null hypothesis
• high p-value: the sample result would be likely if the null hypothesis were ture, retention of the null hypothesis

Question 8

alpha

Answer 8

says how low the p-value must be before the sample result is considered unlikely enough to reject the null hypothesis (0.05)

• if there is a 5% chance or less of a result if the null hypothesis were true, then we rejcet the null hypothesis (result is significant)
• if there is a greater chnace than 5% pf a result if the null hypothesis were ture, the null hypothesis is retained

Question 9

sampling distribution

Answer 9

• probability distribution of a statistic based on a large number of sample from a given popuation
• in each null hypothesis tetsing study, we determine a statistic tat summarizes, as much as possible, all of the hypothesis relevant info of a study (sample dependent)

Question 10

Type 1 error

Answer 10

Rejecting the null hypothesis when it is true

Question 11

Type 2 error

Answer 11

retaining the null hypothesis when it is false