Question 1194813
Ho: NH>= H
Ha: NH< H
alpha=0.05 p{reject Ho|Ho true}
test statistic is a t (0.95, df=37)
critical value is t < -1.687
t=(NH-H)/sqrt (sH^2/n1)+(sNH^2/n2)
=-9/sqrt((49/21)+(16/18))
=-9/1.80
=-5
strongly reject Ho and conclude that the manufacturer's claim is correct.
p <0.0001