# S2 Notes

- 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…

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