Question 1159165
this is a t-test (last statement)
Ho: brand lasts < 40000 miles
Ha: it lasts more
alpha=0.05 P{reject Ho|Ho true|
test statistic is a t 0.95, df=17
critical value is t> 1.74 for a one way test
calculation t=(x bar- mean)/s/sqrt(n)
=503*sqrt(18)/1200
=1.78
because t >1.74, can conclude the tires do last for more than 40,000 miles
p=0.0466