# S2 Notes

HideShow resource information
• Created by: Jessica
• Created on: 19-05-13 15:48

S2 Binomial Distribution
Binomial Distribution

You can use the Binomial distribution to calculate probabilities
when:

There is a fixed number of trials

Each trial should result in success or failure

Trials are independent

Probability is constant

X ~ B(n,p)  n=number of trials
p= probability of success
E(X)= np
Var(X)=np(1-p)

S2 Hypothesis Testing
An hypothesis is a statement made about the value of a population parameter that we wish to test by collecting evidence in the form of a sample.
In a statistical hypothesis test the evidence comes from a sample which is summarized in the form of a statistic called the test statistic.

We form two Hypotheses:
- The null hypothesis,
H0,  we assume to be correct unless proven otherwise.
-
The alternative hypothesis, H1, tells us about the population parameter if our assumption is shown to be wrong.

The critical region is the range of values that lead to a rejection of the null hypothesis.
One tailed test - looks for an increase or decrease in the value.
Two tailed test.
Two critical values
Alternative hypothesis