OZ Lotto Interquartile Range (IQR) Distribution

  Number Frequency   Overdue Numbers   Odd/Even Numbers   High/Low Numbers   Sum and Root Sum   Hot and Cold Numbers   Most Common Pairs   Most Common Triplets   Most Common Quadruplets   Most Common Quintupletss   Mean, STDEV, and Range Trend   Mean Distribution   Range Distribution   STDDEV Distribtion   IQR Distribution   Clustering Distribution
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  Number Frequency   Overdue Numbers   Odd/Even Numbers   High/Low Numbers   Sum and Root Sum   Hot and Cold Numbers   Most Common Pairs   Most Common Triplets   Most Common Quadruplets   Most Common Quintupletss   Mean, STDEV, and Range Trend   Mean Distribution   Range Distribution   STDDEV Distribtion   IQR Distribution   Clustering Distribution

In lottery number analysis, the Interquartile Range (IQR) measures the spread of the middle 50% of drawn numbers. It is also used in showing how tightly or loosely the central values cluster, helping reveal typical spacing behavior in lotto results.

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OZ Lotto Charts

 
Last 75 draws
From Jul. 2, 2024 To Dec. 2, 2025

Box Plot and Histogram of Draw Interquartile Ranges

Below are the box plot of draw results and the histogram of interquartile range. It covers the winning OZ Lotto numbers from Jul. 2, 2024 to Dec. 2, 2025 , across 75 draws over time.

Box Plot of Lotto Draw Results

The chart below displays the statistical distribution, spread, or variability of winning OZ Lotto numbers. The distribution, spread, and variability of winning numbers describe how the numbers are spaced out and how widely they differ from draw to draw. Sometimes they’re close together, sometimes they’re far apart. By examining measures such as quartiles, ranges, and number gaps, we gain insight into the balance and clustering of numbers rather than just their frequency. Quartiles show how numbers divide into lower, middle, and upper sections; the range highlights the gap between the smallest and largest values; and average gaps reveal how closely numbers group together. Studying these metrics is significant because it helps detect patterns of randomness, and spot unusual clustering.

Each box represents the middle 50% of numbers from the first quartile (Q1) to the third quartile (Q3), while the line inside the box marks the median winning number for that period. The “whiskers” extend to the minimum and maximum numbers drawn, and any points outside these whiskers indicate unusually low or high results relative to other draws. By tracking how the quartiles and range shift over time, the chart provides insight into the variability and spread of winning numbers, which can be used to visually assess the randomness and consistency of lotto draws.

Across all draws, the middle 50% of numbers showed moderate spread, suggesting balanced variability. Overall, higher numbers tended to dominate the draws. Number distribution across ranges was generally balanced.

Histogram of Draw Interquartile Ranges

The histogram of interquartile ranges (IQR) focuses on the spread of the middle 50% of lotto numbers within each combination. By dividing these IQR values into bins, the histogram shows whether draws are typically compact or widely varied in their core distribution. This measure avoids extreme outliers and reveals the consistency of number spacing.

The histogram of interquartile ranges (IQR) of lotto draws reveals that the most frequent IQR interval is 12-17 with 22 occurrences, suggesting a strong clustering in this interval. In contrast, the least frequent IQR interval is 0-5, 36-41, 42-44 with 0 occurrences, showing it is rarely observed. This indicates a noticeable concentration of draws around certain IQR intervals. Overall, the distribution shows clustering around specific IQR intervals, indicating that draws tend to gravitate toward these values.

Format Changes in Australia's Oz Lotto

Oz Lotto, Australia’s first national lottery, has undergone several format changes since its launch in 1994. Below is the timeline of the Australia's Oz lotto format changes:

Period Format Supplementary Nos.
1994 - Oct. 11, 2005 6 numbers from a pool of 45 (6/45) 2 numbers from the same pool.
Oct. 18, 2005 - May 10, 2022 7 numbers from a pool of 45 (7/45) 2 number from the same pool.
May 17, 2022 - Present 7 numbers from a pool of 47 (7/47) 3 number from the same pool

Initially, the game required players to select six numbers from a pool of 45, and two supplementary numbers were drawn to help determine secondary prizes. In October 2005, the format was modified to increase the number of main numbers drawn from six to seven, still from a pool of 45, while retaining two supplementary numbers. This change made the jackpot more difficult to win but allowed for larger prize pools. In May 2022, Oz Lotto underwent another significant update. The number pool was increased from 45 to 47, while the game continued to draw seven main numbers. Additionally, the number of supplementary numbers increased from two to three. Along with this change, the minimum jackpot prize was raised from $2 million to $3 million, and the overall odds of winning any prize improved, creating more opportunities for players to win across additional prize divisions. These changes reflect Oz Lotto's ongoing efforts to remain engaging and competitive within Australia’s lottery landscape.

How Australia's Oz Lotto 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 6/45 format may have done so due to higher individual draw probability, but that same frequency can be misleading in the 7/45 or 7/47 formats. Furthermore, changes to the number pool also significantly affect how often a specific supplementary numbers appear.

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.

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