The Standard Deviation is also very useful in analyzing how spread out the numbers tend to be from draw to draw. It also shows how consistently random the draws are over time

Last 75 draws
From Jul. 23, 2025 To Nov. 29, 2025

Histogram of Standard Deviation

The histogram of standard deviation measures how much variation or dispersion exists among numbers in each lotto draw. A low standard deviation means the numbers are close together, while a high standard deviation indicates they are spread out across the range. By dividing these values into bins, the histogram reveals whether draws tend to produce tightly grouped numbers or broadly spaced sets. This helps in understanding the randomness and variability of number distribution across many draws.

The chart below is a histogram of standard deviation of lotto combinations from Jul. 23, 2025 to Nov. 29, 2025 , covering 75 draws. The range of possible standard deviation is divided into categories or bins. In this case, the bins are defined as intervals such as 1-5 up to 36-39, each representing a continuous range of mean values.

This division is necessary because individual standard deviation values can vary widely, and grouping them into intervals makes patterns easier to observe. For example, by examining how frequently standard deviation fall into each bin, anyone can quickly see whether the draws are evenly distributed, clustered in particular ranges, or biased toward lower or higher values.

The histogram of standard deviations of lotto draws, showing how widely numbers vary within combinations reveals that the most frequent deviation interval is 11-15 with 26 occurrences, suggesting a strong clustering in this interval. In contrast, the least frequent deviation interval is 16-20, 21-25, 26-30, 31-35, 36-39 with 0 occurrences, showing it is rarely observed. This indicates a noticeable concentration of draws around certain deviation intervals. Overall, the distribution shows clustering around specific deviation intervals, indicating that draws tend to gravitate toward these values.

Format Changes in UK Thunderball

Since its launch in June 1999, the UK Thunderball lottery has undergone several key format changes aimed at enhancing the game and increasing player excitement. These adjustments have expanded the number selection pool.

Period Format Thunderball
June 1999 5 numbers out of 34 1 number out of 14
May 9, 2010 5 numbers out of 39 1 number out of 14

Throughout these changes, the Thunderball number has always been drawn from its own pool of 14 numbers, separate from the main numbers, preserving the structure that has defined the game since its creation.

How Thunderball Format Changes Affect Your Number Strategy.

These format changes have a direct impact on statistical analysis. Mixing frequency data across different formats is not advisable because each version of the game has a different number pool and probability structure.

For example, a number that appeared frequently in the 5/34 number format may have done so due to higher individual draw probability, but that same frequency can be misleading in the 5/39 format.

Therefore, for meaningful analysis, it’s essential to treat each format as its own distinct dataset. Analyzing trends or frequencies should be restricted to results from within the same format period, especially if the goal is to inform number selection in the current game structure.