Homework Help: math

Posted by Jon on Saturday, February 9, 2008 at 4:25pm.

2)For 2000 patients, a blood-clotting time was normally distributed with a mean of 8 seconds and a standard deviation of 3 seconds. What percent had blood-clotting times between 5 and 11 seconds?
A)68%
B)34%
C)49/5%
D)47/5%
I chose A

4)A music teacher wants to determine the music performances of students. A survey of which group would produce a random sample?
A)students in the school band
B)students attendeing the annual jazz concert
C)students in every odd-numbered homeroom
D)every other player on the baseball roster
is it A?

math - DanH, Saturday, February 9, 2008 at 4:31pm
2) A is correct
4): I think the point of this question is that the teacher wants a RANDOM sample of students. The only choice that would really give her a random sample would be C. All others are biased.
math - BIAO, Monday, September 5, 2011 at 5:51am
POITS A,B, AND C ARE COLLINEAR .AB=7CM BC =13CM WHATIS AC ANSWER

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