<p>@commodore
The answer should be C
The way you do it is first invnorm(.67). This gets you the z score of the diameter
Then you multiply .3 times this number and u get .132. Its above the mean because its the 68th percentile, which is above 50 (the middle value)</p>
<p>What about this one? Its really hard 
<a href=“http://www.kent.k12.oh.us/~ke_bmccombs/apstatsl/Exam%20review/2008%20released%20exam.PDF[/url]”>http://www.kent.k12.oh.us/~ke_bmccombs/apstatsl/Exam%20review/2008%20released%20exam.PDF</a> number 40</p>