In this Demonstration, you can set the number of coin flips per trial to 5, 10 or 20, and the number of heads is recorded. Set the total number of trials (from 1 to 10,000) with a button. When the probability of heads is 50%, the distribution closely resembles a normal distribution as the number of trials and the number of coin flips per trial increase. AS the sample size increases, the distribution more closely resembles a true binomial distribution. Make a weighted coin by changing the probability of landing on heads using the slider; 0% means the coin always lands on tails and 100% means the coin always lands on heads. Click "flip coins" to generate a new set of coin flips. Use buttons to view a bar chart of the coin flips, the probability distribution (also known as the probability mass function), or the binomial distribution. The probability mass function is the number of flips in a trial that resulted in heads divided by the number of flips.