Question

assume fhag females have pulse rates that are normally distributed with a mean of 72.0 beats per minute and a standard deviation of 12.5 beats per minute. If 1 adt female is randomly selected find the probability that her pulse is between 65 beats per minute and 79 beats per minute.

if 16 adult females are randomly selected find the probability that they have pulse rates with a mean between 65 minutes and 79 minutes per minute

Answer 1

Solution :

Given that ,

mean = = 72.0

standard deviation = = 12.5

P( 65< x < 79 ) = P[(65 -72)/12.5 ) < (x - ) /  < (79 -72) /12.5 ) ]

= P( -0.56< z < 0.56)

= P(z < 0.56 ) - P(z < -0.56 )

Using standard normal table

= 0.7123 - 0.2878 = 0.4245

Probability =0.4245

n = 16

= = 72.0

= / n = 12.5 / 16 = 3.125

P(65 < < 79)  

= P[(65 -72) /3.125 < ( - ) / < (79 -72) /3.125 )]

= P( -2.24< Z < 2.24)

= P(Z < 2.24) - P(Z < -2.24 )

= 0.9875 - 0.0125 = 0.9750

probability = 0.9750