Difficult True or False Probability Question. Can anyone help show how they solved this problem?

A manufacturer of light bulbs claims that his light bulbs have a mean life, m , of 1150 or more hours with a standard deviation of 80 hours. A random testing of 36 light bulbs yielded a mean of 1125 hours.





True or false: There is evidence, at 伪= 0.005, to reject the null hypothesis, H0: 碌 %26gt; 1150








True or FalseDifficult True or False Probability Question. Can anyone help show how they solved this problem?
Let's name


m=1150


s=80


n=36


m*=1125(instead of 渭)


level of confidence


a=0.005


In order to accept H0:m*%26gt;1150


Must


(m*-m)/[s/sqr(n)]%26gt;


Z


1-a


.





(1125-1150)/[80/6]%26gt;


Z


0.995


-15/8%26gt;2.5(from statistic tables)


It is wrong,so we must


reject it