Uploaded December 2012 | Updated September 2026, 2 hours ago
I introduce the chi-square test for one-way tables (sometimes called a goodness-of-fit test), and work through an example.
The data used here is from a classic 1905 genetics experiment by William Bateson and Reginald Punnet.
I introduce the chi-square test for one-way tables (sometimes called a goodness-of-fit test), and work through an example.
The data used here is from a classic 1905 genetics experiment by William Bateson and Reginald Punnet.
![Finding the Appropriate z Value for the Confidence Interval Formula (Using a Table)
I show how to find the appropriate z value (using the standard normal table) when calculating a confidence interval. The version of the table used in this video gives the area to the left of the z value (and not the area between 0 and z).
For those that use R, below is the R code to find the values (see the video for illustrations).
z value for a 95% interval:
qnorm(.975)
[1] 1.959964
z value for a 75% interval:
qnorm(.875)
[1] 1.150349 Finding the Appropriate z Value for the Confidence Interval Formula (Using a Table)](https://i.ytimg.com/vi/grodoLzThy4/mqdefault.jpg)





![Introduction to the Continuous Uniform Distribution
A brief introduction to the (continuous) uniform distribution. I discuss its pdf, median, mean, and variance. I also work through an example of finding a probability and a percentile. I dont do any integration in this video.
For those using R, here is the R code to find the probabilities for the examples in this video:
P(X greater than 230) where X is U(200,250):
1-punif(230,200,250)
[1] 0.4
(punif yields the area to the *left*, and here we need the area to the *right*)
20th percentile of a U(200,250) distribution:
qunif(.2,200,250)
[1] 210 Introduction to the Continuous Uniform Distribution](https://i.ytimg.com/vi/izE1dXrH5JA/mqdefault.jpg)
![An Introduction to the Poisson Distribution
An introduction to the Poisson distribution. I discuss the conditions required for a random variable to have a Poisson distribution. work through a simple calculation example, and briefly discuss the relationship between the binomial distribution and the Poisson distributions.
Plutonium-239 example (an average of 2.3 radioactive decays per second).
Finding the probability of exactly 3 radioactive decays in a 2 second period:
dpois(3,2*2.3)
[1] 0.1630676
Finding the probability of no more than 3 radioactive decays in a 2 second period:
dpois(0,2*2.3)+dpois(1,2*2.3)+dpois(2,2*2.3)+dpois(3,2*2.3)
[1] 0.3257063
or
ppois(3,2*2.3)
[1] 0.3257063 An Introduction to the Poisson Distribution](https://i.ytimg.com/vi/jmqZG6roVqU/mqdefault.jpg)


