Posted by **Laura** on Sunday, January 3, 2010 at 4:41pm.

Of all U.S. fourth graders, 71% are assigned mathematics homework three or more times per week. If 5 fouth graders are randomly selected to be checked for this frequency of homework assignment during a randomly chosen week, find the probability that

A.) exactly one fourth grader was assigned homework three or more times that week

B.) no fourth grader was assigned homework three or more times that week

C.) at least one fourth grader was assigned homework three or more tiems that week

- AP Statistics -
**bobpursley**, Sunday, January 3, 2010 at 4:49pm
a)

NNNNY

NNNYN

NNYNN

NYNNN

YNNNN

so, there are five ways to sort the fourth graders

Pr(one)=5*.71*.29^4=.0251 check that.

b)Pr(none)=.29^5

c) Pr(at least one)=1-Pr(none)

- AP Statistics -
**sally**, Friday, January 13, 2012 at 11:18am
A. .0251

B. .0020

C. None

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