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Poker test, 10,000 five-digit numbers (2072)

Short answer

For five‑digit numbers, expected frequencies from probabilities give χ0² = 318.37. With 6 degrees of freedom and α=0.05 critical value 12.592, since 318.37 > 12.592, the null hypothesis of independence is rejected.

A sequence of 10,000 five digit numbers has been generated and analysis indicates the following combinations and frequencies.

Combinations (i)Observed Frequency (Oi)
All different3450
One pair4510
Two pair1150
Three of a kind750
Full house85
Four of a kind40
Five of a kind15
Total10,000

Based on Poker Test check whether the numbers are independent. Use α = 0.05 and N = 6 is 12.592

Setup. H0: the numbers are independent. H1: they are not. N = 10,000, 7 classes, so df = 6 and χ²0.05,6 = 12.592.

For five-digit numbers, counting the 10⁵ equally likely strings gives the probabilities: all different 0.3024, one pair 0.5040, two pairs 0.1080, three of a kind 0.0720, full house 0.0090, four of a kind 0.0045, five of a kind 0.0001 (they sum to 1).

Expected frequency Ei = 10,000 × probability.

PatternProbabilityOiEi(Oi − Ei)²/Ei
All different0.30243450302460.012
One pair0.5044510504055.734
Two pair0.108115010804.537
Three of a kind0.0727507201.250
Full house0.00985900.278
Four of a kind0.004540450.556
Five of a kind0.0001151196.000

χ0² = 318.37

Conclusion. Since 318.37 > 12.592, H0 is rejected. The numbers are not independent. The large deviations are in "all different" (3450 against 3024 expected), "one pair" (4510 against 5040), and "five of a kind" (15 against 1). Even after merging the two smallest classes, the statistic stays far above the critical value.

✓ Answer checked by Claude Opus 5.5 (high effort)

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