Question

The number of accidents in a highway as recorded every month over a 9 month period are 15,18,9,11,14,10,8,13,19. Test at 5% frequencies are in in agreement with the belief that the number of accidents was the same during the 9 months. it is given that the table values of x² at 5% level for 8 d.o.f. are 15.5 and 16.9 respectively.

Answer 1

Let,

$H_o:$ The number of accidents ocur during 9 months are same with expected frequencies $(E_i=\dfrac{N}{9}=\dfrac{117}{9}=13)$

The distribution table is-

The value of $\chi^2=\sum{\dfrac{(O_i-E_i)^2}{E_i}}=\dfrac{100}{13}=7.6932$

The tabulated value of $\chi^2$ at 8 d.o.f. is 16.9

Conclusion: As the calculated value of $\chi^2$ is less than the standard value so, Null hypothesis is accepted i.e. Number of accidents are same.