[طموح بيشو]

مااعرفت احلها

30. Find two z values so that 41.08% of the middle area is bounded by them
A) ± 1.35
B) ± 0.4108
C) ± 0.54
D) ± 0.2054


\

25. The average weight of books on a library f is 8.3 grams. The standard deviation
is 0.6 grams. If 20% of the books are oversized , find the minimum
weight of the large books on the library f. Assume the variable is normally
distributed.
A) 8.612 grams
B) 0.3 gram
C) 0.84 gram
D) 8.804 grams




22. In a certain school, it is known that 81% of instructors are using e-mail to send
messages. For a sample of 10 instructors, find the probability that exactly 6 of them
are using e-mail.
A) 0.0773
B) 0.0004
C) 0.2824
D) 0.0043