Form the confidence level (99%), we calculate the "alpha" value
alpha=1-(99/100)=0.01
Now, calculate the critical probability (p-start)
p*=1-(alpha/2)=1-(0.01/2)=0.995
z-score could be calculated from p*,,,
z-score=2.57583
Now, calculate the Margin of Error:
standard deviation = s
number of adults = n
ME=(z*s)/(sqrt n)=(2.57583*12)/(sqrt 250) = 1.955
The confidence interval = mean +or- ME
= 70+1.955 or 70-1.955
So that we can conclude that the 99% confidence interval for the mean beats per minute is 68.045 and 71.955
I hope you got the idea!
