IDNStudy.com, kung saan ang kuryusidad ay nagtatagpo ng kalinawan. Ang aming mga eksperto ay nagbibigay ng mabilis at eksaktong sagot upang tulungan kang maunawaan at malutas ang anumang problema.

A certain type of battery has a mean shelf life of 600 days with a standard deviation of 28 days.

a. What is the probability that the shelf life of the battery is over 630 days?


b. What is the probability that the shelf life of the battery is between 400 days and 550 days?


please help me​


Sagot :

a.

z = [tex]\frac{630-600}{28}[/tex] =  1.071

P(z>1.071)

b.

z=[tex]\frac{400-600}{28}=[/tex] [tex]-\frac{200}{28} =-7.14[/tex]

z=[tex]\frac{550-600}{28} =[/tex][tex]-\frac{50}{28} = -1.78[/tex]

P(-7.14<z<-1.78)