4. Accidents occur randomly at a crossroads at a rate of 0.5 per month. A researcher records the number of accidents, \(X\), which occur at the crossroads in a year.
- Find \(\mathrm { P } ( 5 \leqslant X < 7 )\)
A new system is introduced at the crossroads. In the first 18 months, 4 accidents occur at the crossroads.
- Test, at the \(5 \%\) level of significance, whether or not there is reason to believe that the new system has led to a reduction in the mean number of accidents per month. State your hypotheses clearly.
| VIIIV SIHI NI JIIIM ION OC | VIIV SIHI NI JAHM ION OO | VI4V SIHI NI JIIIM I ON OO |
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