Question

An environmental impact assessment conducted in the wake of COVID19 lockdown assessed the difference in toxic air particles’ exposure in following two samples: 1. 100 construction workers in Defence Lahore 2. 120 construction workers in Sundar Industrial Estate (SIE) The mean exposure of workers in Defence was 20 mg/m3 with a standard deviation of 8 33 mg/m . For workers in SIE, the mean exposure was 10 mg/m with a standard deviation of 3 2.5 mg/m . (a) Use a 90% confidence interval to describe the difference in the exposures. (b) Test the null hypothesis that the exposures for these two types of workers are the same.

Answer 1

a) 90% Confidence interval to difference in the expoposures is

b) Test the null hypothesis that the exposures for these two types of workers are the same.

(1) Null and Alternative Hypothsis:

H0: the exposures for these two types of workers are the same.

H1: the exposures for these two types of workers are not the same.

i.e. thus we conclude that  the exposures for these two types of workers are not the same.