Skip to main content

Poker test, 1000 four-digit numbers (2070 Magh)

Short answer

The chi‑square statistic is 39.19, with 4 degrees of freedom and critical value 9.49 at α=0.05. Since 39.19 > 9.49, the hypothesis of independence is rejected.

A sequence of 1000 four digit numbers has been generated and analysis indicates the following combinations and frequencies:

Combination (i)Observed Frequency (Oi)
Four different digits540
One pair380
Two pairs54
Three like digits25
Four like digits1
1000

Based on poker test check whether the numbers are independent. Use α=0.05 and χ² = 9.49

Setup. H0: the numbers are independent. H1: they are not. N = 1000, five classes, df = 4, α = 0.05, χ²0.05,4 = 9.49.

Probabilities for four-digit numbers: 0.504, 0.432, 0.027, 0.036, 0.001. Ei = 1000 × probability.

PatternProbabilityOiEi(Oi − Ei)²/Ei
Four different0.5045405042.571
One pair0.4323804326.259
Two pairs0.027542727.000
Three of a kind0.03625363.361
Four of a kind0.001110.000

χ0² = 39.19

Conclusion. Since 39.19 > 9.49, H0 is rejected; the numbers are not independent. The biggest contribution is from "two pairs" (54 against 27 expected, contribution 27.0).

✓ Answer checked by Claude Opus 5.5 (high effort)

All Simulation and Modeling chapter 6 questions →