هنآ: اسئلتكم في مآدةة الاحصآء

[فطوم A]

32. The average repair cost of a microwave oven is $55, with a standard
deviation of $8. The costs are normally distributed. If 12 ovens are repaired, find the
probability that the mean of the oven repair will be greater than $60.
A) 0.015
B) 0.4850
C) 0.2643
D) 0.985


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

ابغى حل السؤالين =)