Question

Suppose that your average heart rate is 72. The average heart rate in your class is 82 and the variance is 25.
a[10 points] What percent of the class has a lower heart rate?
b[10 points] If there are 100 students in your class, how many students have a higher heart rate (the actual number not the percentage)?

Answer 1

Let X be the average heart rate of a student .

X has mean ,82 and variance 25

So , using CLT we can say :

a) to find probability of student having lower heart rate than that of yours, which is 72.

So

  

  

So , 2.28% of students have lower heart rate .

b) Here we need to find probability of students having higher heart rate .

  

So, out of 100 , np'= (100 x 0.772) = 77.2 77 students have higher heart rate.