Simple Interactive Statistical Analysis
Zero Truncated Binomial
Input.
Input for the mean or average of a counted number the value in the Expected box can be any (decimal) number larger than one. The mean can also be entered as a proportion expected, a value between zero and one. Input for the number Observed and for the Sample size box must be integer values, positive number without decimals.
Explanation.
The zero truncated Binomial distribution concerns a Binomial distribution without zeros. For example, you want to know if the number of different items people buy in a shop follows a Binomial distribution, then, when you check this at the cash register, you will not see any people with zero items. The upper limit of the number of different items people can choose from is in this example the sample size.
Philosophically this distribution has exactly the same properties as the usual Binomial distribution and the user is therefore for further information referred to the Binomial discussion.
Note that in the zero truncated binomial distribution the relationship between the proportion and the distribution mean is different and considerably more complex than in the usual Binomial procedure. If you input the mean expected count (the average number of different items you expect in peoples shopping baskets) the program will echo the expected proportion, the variance and part of the distribution. The mean should have a value above one. The mean can also be entered as a proportion, a value between zero and one, for example, if you want to enter the proportion of available items people have on average in their shopping basket. The program will echo the mean and the rest. The proportion should have a value above zero.
Please study the binomial distribution further by using the Binomial spreadsheet
