Summary Statisticians collect the data to investigate the characteristics of a population. After taking a sample it is assumed that the result for the sample reflects the whole population. Some important terms that we must be familiar with are: Census, Sampling unit and sampling frame. Random Sampling: his method gives every item of the population … Read more

Random Samples

Summary Random Samples is known as the collection of independent and identically distributed random variables such as Sample mean is considered a normal distribution which is represented as: The expected value also known as mean can be calculated as: Variance is a measurement of the spread between numbers in a data set. It can be … Read more

Permutations and Combinations

Summary Permutations are ways in which an element from a set is selected considering that the order is significant when repetition is not allowed when repetition is allowed Combinations are defined as ways in which an element from a set is selected, such that the order of selection does not matter when repetition is not … Read more

One & Two Tailed Tests

Summary Hypothesis in simpler words is basically a claim that we want to test or investigate The ”Null Hypothesis” denoted as , this means testing a claim that already has some established parameters The ”Alternative Hypothesis” is denoted as , this is known as the research hypothesis. It involves the claim to be tested One … Read more

Normal Approximation To The Binomial

Summary Normal Approximation to the Binomial Distribution:Mean: & Variance: ,  If say that X follows a poisson distribution with parameter i.e , then Normal distribution can be used as an approximation where . Continuity correction is to either add or subtract 0.5 of a unit from each discrete X value. In this article we will … Read more

Measures of Dispersion

Summary Variance: Standard deviation: Grouped data Mean = Variance = Quartiles Lower quartile can be found by calculating a way up ( median between 0 and the median value) Upper quartile by taking of the y axis ( half way between the median value and the maximum frequency) Interquartile = upper quartile – lower quartile … Read more