## 5.1 Quick revision

We recommend trying these Quick revision questions before your tutorial.

A study of how well emergency dispatchers recognised signs of stroke collected the data shown below.

Sex of patients Dispatcher suspected stroke Dispatcher missed stroke
Male 67 43
Female 97 39
1. What percentage of male patients had their stroke symptoms missed by the dispatcher?
2. What percentage of female patients had their stroke symptoms missed by the dispatcher?
3. What are the odds that a male patients had their stroke symptoms missed by the dispatcher?
4. What are the odds that a female patients had their stroke symptoms missed by the dispatcher?
5. What is the odds ratio that a patients had their stroke symptoms missed by the dispatcher, comparing males to females?
1. $$43\div (43 + 67) \times 100 = 39.1$$%.
2. $$39\div (97 + 39) \times 100 = 28.7$$%.
3. $$43\div 67 = 0.642$$.
4. $$39\div 97 = 0.402$$.
5. $$0.642 \div 0.402 = 1.6$$.

### References

Oostema JA, Chassee T, Reeves M. Emergency dispatcher stroke recognition: Associations with downstream care. Prehospital Emergency Care. 2018;22(4):466–71.