What is statistical inference?
Using what we know about a sample to make probabilistic statements about broader population
What is s population parameter?
Quantity of population
What is a sample statistic?
A quantity of the sample (provides an estimate of the population parameter)
What is a sampling distribution?
Get a random sample and find the mean then the distribution of all these possible sample means
What are the 2 types of estimates?
Point and interval/confidence
What is point estimate?
Single number that is best guess for parameter value
What is interval/confidence estimate?
An interval of numbers around the point estimate that we believe with some confidence contains parameter value
What is the formula for confidence interval?
[point estimate – margin of error; point estimate + margin of error]
How to correctly interpret the confidence interval?
We are 95% confident that the interval […,…] contains the mean population age
What are significant tests?
Uses data to summarise the evidence about a hypothesis, by comparing point estimates of the parameters within the values predicted by the hypothesis
What are the 5 parts of significance tests?
Assumptions, hypotheses, test statistics, p-value, conclusion
What is are the assumptions?
Type of data (qualtitiative, interval or ratio), Independence, randomisation, population distribution
What are the 2 types of hypotheses?
Null and alternative (proof by contradiction)
What is tests statistics?
Summarises how far the estimate falls from the parameter value null, and the standard number of errors
What is the p-value
Probability that test statistic = observed value
What does a smaller p-value mean?
That the evidence against the null hypothesis is stronger
What is the Alpha level?
The level of significance, must be selected before analysing the data and is used to compare against p value
What is the conclusion?
Report and interpret p-values
