time study in industrial management

Question

(a) In a stop watch time study, the actual readings in minutes, recorded for an element are:

0.05	0.06	0.05	0.05	0.05	0.06	0.06
0.05	0.06	0.06	0.06	0.06	0.05	0.05
0.06	and	0.05

 

1. Have sufficient number of readings been taken for 95% confidence level and ± 5% accuracy?
2. If the rating is 120%, what would be the normal time for the element?
3. What would be the standard time for the element if the personal needs allowance, fatigue allowance and contingency allowance are 5%, 6% and 5% respectively?
4. What is the purpose of providing contingency allowance? Give two examples.