Assume that heart rate (in beats per minute, or bpm) before an .... for STA 100
ID: 3333287 • Letter: A
Question
Assume that heart rate (in beats per minute, or bpm) before an .... for STA 100 students is distributed normal, with a mean of 95 bpm and a standard deviation of 18.5 bpm. Assume all students in the following problem are selected from this population
c. What is the first quartile of heartrates for randomly selected students?
d. What is the third quartile of heartrates for randomly selected students?
e. What is the 8th percentile for heart rates among randomly selected student?
f. If we know a randomly selected students heart rate is over 100 (it is given), what is the probability that it is under 125?
Explanation / Answer
c)as we know that for first quartile lies at 25th percentile for whcih z =-0.6745
hence corresponding heartrate =mean +z*std deviation =82.52
d) for third quartile lies at 75th percentile for whcih z =0.6745
hence corresponding heartrate =mean +z*std deviation =107.48
e) for 8th percentile z =-1.4051
hence corresponding heartrate =mean +z*std deviation =69.01
f)P(X<125|X>100) =P(100<X<125)/P(X>100) =P(0.2703<Z<1.6216)/(1-P(Z<0.2703))
=(0.9476-0.6065)/(1-0.6065)=0.5623