Posted by **UPD** on Thursday, April 15, 2010 at 3:13am.

Information given:the distribution of male head circumference (HC) is normal with a mean of 56cm and a standard deviation of 1.8cm

first question

-the prob that HC of a random chosen man is larger than 57.8cm is?

Work: pr(x)>57.8cm

z=(57.8-56)=1.8--->.9641 i got it wrong?

Second ques:

what is is the sampling distrubution of the avg HC of 9 random selected men?

Third: the prob that the average HC of 9 random selected men is larger then 57.8cm is?