Pages
Archives

Recent Posts
Categories
 5number summary Alternative Hypothesis American roulette Bar Graph Benford's Law Bill Gates Binomial Coefficient Binomial distribution Binomial Experiment Birthday Problem Blaise Pascal Chevalier de Mere Chisquare goodness of fit Chisquare statistic Chisquare test Completely Randomized Experimental Design Conditional distribution Confidence Interval Confounding Correlation Critical Value Cryptography Descriptive statistics Diabetes DoortoBalloon Time Double blind Empirical Rule Expected value Experiments First Quartile Gambling Games of chance Games of dice Histogram Interquartile Range Introduction to statistics Introductory statistics Joint distribution LeastSquares Regression Lurking variables Marginal distribution Matched Pairs ttest Mean Median Normal Curve Normal Distribution Null Hypothesis Observational studies OneSample tProcedures OneSample ttest pvalue Paul Allen Percentile Placebo Probability Randomized Experiments Reasoning of Statistical Inference Regression Line Residual Plot Residuals Resistant numerical summary Sampling Distribution Scatterplot Standard Deviation Statistical Inference Statistics In Action Stemplot ttest Tests of Significance The law of large numbers Third Quartile Time Plot Twoway tables Uniform Distribution Warren Buffet
Category Archives: Probability
The probability of breaking the bank
What is the likelihood of a gambler winning all the cash in a casino? A better question is: what is the likelihood of a gambler losing all the money he or she brings into the casino? There had been casinos … Continue reading
Benfordâ€™s Law and US Census Data, Part II
The Benford’s law is a probability model that is a powerful tool for detecting frauds and data irregularity. The first digit (or leading digit) of a number is the leftmost digit and can only be 1, 2, 3, 4, 5, … Continue reading
Posted in Probability, Statistical Inference, Statistics
Tagged Alternative Hypothesis, Benford's Law, Chisquare goodness of fit, Chisquare statistic, Chisquare test, Introduction to statistics, Introductory statistics, Null Hypothesis, pvalue, Statistical Inference, Tests of Significance
2 Comments
Benford’s Law and US Census Data, Part I
The first digit (or leading digit) of a number is the leftmost digit (e.g. the first digit of 567 is 5). The first digit of a number can only be 1, 2, 3, 4, 5, 6, 7, 8, and 9 … Continue reading
Is It Possible to Spot Fraudulent Numbers?
People engage in financial frauds have a need to produce false data as part of their criminal activities. Is it possible to look at the false data and determine they are not real? A probability model known as the Benford’s … Continue reading
Rolling Dice to Buy Gas
The price of gas you pay at the pump is influenced by many factors. One such factor is the price of crude oil in the international petroleum market, which can be highly dependent on global macroeconomic conditions. Why don’t we … Continue reading
The Middle 80% Is Not 80th Percentile
A student sent me an email about a practice problem involving finding the middle 80% of a normal distribution. The student was confusing the middle 80% of a bell curve with the 80th percentile. The student then tried to answer … Continue reading
Coin Tossing and Family Size
If you a toss a coin 9 times, what is the probability of obtaining 8 heads and 1 tail? I just tossed one penny 9 times and the following is the resulting sequence of heads and tails. The above little … Continue reading
The Osmond Brothers – a Binomial Example
According to Wikipedia, the Osmonds are an American family music group with a long and varied career – a career that took them from singing barbershop music as children, to achieving success as teenmusic idols, to producing a hit television … Continue reading
The Birthdays of the Presidents of the United States
How likely is it to find two people with the same birthday in a group of partygoers? If the group only has 2 or 3 people, it is probably not likely. So how many people do you need to have … Continue reading