Tutor Stats

Introduction to Normal Distribution #2

We learned about the normal distribution in the first article. We will solve the practice problems shown in the first article to familiarize ourselves with this distribution Empirical Rule problem Find out the percentage of the following data from above example with mean 60 and standard deviation 15 and sample size 10,000. What percentage of shells have size below 75mm ?When looking at the empirical rule of normal distribution we… Read More »Introduction to Normal Distribution #2

Random Data files #1

Some data files for forming and solving statistical problems. Use the appropriate statistical processes for solving the problems. You can find stat tables here for reference. Tail wags and Chew toys A study was conducted, at a pet clinic with 200 randomly chosen dogs, to find which toy was more popular toy 1 or toy 2. Download the data file below Height of School kids height of 300 school kids… Read More »Random Data files #1

Introduction to Poisson Distribution #1

Poisson Distribution curve is one of the most used statistical methods used for predicting event occurrence probability based on historical data of said event. Corporations use the Poisson distribution to predict sales for a financial quarter based on sales of the previous three quarters. Meteorologists use historical data to predict weather patterns for the upcoming year. Probability Mass Function The probability mass function of the distribution is given by the… Read More »Introduction to Poisson Distribution #1

Introduction to ANOVA #1

ANOVA stands for Analysis of Variance. This is a collection of statistical methods used in experiments that contain multiple treatments and groups. The populations of the samples of collected data may not follow normal distribution curve. Experimental Design For every ANOVA test, there has to be an experiment designed that enables the use of the process. This involves multiple steps that include: subject of investigation level of significance range of… Read More »Introduction to ANOVA #1

Introduction to Regression Analysis #1

Regression Analysis is one most used statistical methods in practical applications. It is used to study trends of data and needs a minimum of 2 variables for the simplest analysis. Which multiple variables? In regression analysis we need at least 2 variables for the simplest calculations. The first variable is called Dependent variable and the second is called Independent variable. We use the calculations to see if changing the values… Read More »Introduction to Regression Analysis #1

T table and how to use it Easily

The T table shows values of critical T values that correspond to Degree of Freedom and Level of significance of the test. Degree of Freedom The Degree of freedom or DF is calculated with the simple formula: DF = n – 1where n = sample size Level of Significance The level of significance is most commonly known as ALPHA value of the statistical study. The alpha level is decided by… Read More »T table and how to use it Easily

Quick Introduction to T distribution #1

What is T distribution? The Student’s T distribution which is commonly known as T distribution is used when the sample size of a statistical study is small and the population variance is not known. The T distribution curve looks very similar to a normal distribution at first glance, however the curve may be narrower or fatter depending on the Degrees of freedom of the sample size and the distribution of… Read More »Quick Introduction to T distribution #1

Introduction to Binomial Distribution #1

What is binomial? The term binomial means consisting of TWO terms. In the world of statistics and probability this means an event that can have only TWO results. These events have to be mutually exclusive, that is if one occurs then the other event cannot occur. So,e examples of mutually exclusive events are given below: tossing coin for heads / tails passing or failing a test an old machine that… Read More »Introduction to Binomial Distribution #1

Introduction to Normal Distribution #1

What is a Normal Distribution? The most commonly found distribution is known as the Normal Distribution. It takes the shape of the bell curve. The average value has the highest frequency and the frequency of values larger or smaller values than the average taper off in a descending curve. The Normal Distribution has a peculiar property where the mean = median = mode. The curve is seen to be symmetric… Read More »Introduction to Normal Distribution #1