The scientific method Hypothesis testing One and two-tailed test

Question 1

What is The ‘hypothetico-deductive’ method?

Answer 1

The hypothetico-deductive model or method is a proposed description of the scientific method.

According to it, scientific inquiry proceeds by formulating a hypothesis in a form that can be falsifiable, using a test on observable data where the outcome is not yet known. A test outcome that could have and does run contrary to predictions of the hypothesis is taken as a falsification of the hypothesis. A test outcome that could have, but does not run contrary to the hypothesis corroborates the theory. It is then proposed to compare the explanatory value of competing hypotheses by testing how stringently they are corroborated by their predictions.

Question 2

Why is it important?

the hypothetical deductive method

Answer 2

• observation
• Model
• hypothesis
• experiment
• report results

Question 3

What does a good experiment result in?

Answer 3

1. Reject the hypothesis (the model must be wrong)
2. Support the hypothesis ( support for the model)

A good hypothesis must therefore be capable of rejection (falsifiable)
Without a good hypothesis (and model and observations), a well designed and analysed experiment is of little value

Question 4

why is it impossible to prove a hypothesis?

Answer 4

Cannot be 100% sure tha it is correct, one can only gather evidence to support it.
but it is possible to 100% reject a hypothesis - A hypothesis that can repeatedly not being disproved, becomes an acceptable hypothesis.

Question 5

What is a null hypothesis?

Answer 5

There is NO difference between the means.

A=B

Question 6

Wha is an alternative hypothesis?

Answer 6

There IS a difference in the means

We may be interested in the response of a variable relative to another (x = caloric content versus y = hydration state). We may propose several alternates:
1. x increases with an increase in y,
2. x decreases with an increase in y.

However, the null hypothesis remains the same, the rate of x does not influence y

Question 7

What is a one tailed test, what what is the p-value?

Answer 7

In a one-tailed test, the entire significance level is allocated to one tail of the distribution.
p>=0.05

Question 8

What is a two tailed test?

Answer 8

In a two-tailed test, you have two regions each constituting 2.5% of the area under the curve.
Any data point landing in these extreme regions would be considered statistically significant at the 0.05 level, leading you to reject the null hypothesis.

Question 9

What is descriptive statistics?

Answer 9

used in the description of large datasets (e.g. population census data)

Question 10

What is inferntial statistics?

Answer 10

used to draw inferences (make statements) about a population from a sample
Population: dataset that we are interested in
Sample: subset of data selected from the population