AP® Statistics

Free Version

Upgrade subject to access all content


Meaning of a Confidence Interval: Growth Spurt


Boys tend to hit their growth spurt around 13 years old. A random sample of $100$ boys was taken to find out how many inches they grew from thirteen to fourteen years old. A $98\%$ confidence interval was constructed from this data and yielded a result of $(2.8, 4.3)$ inches.

Which of the following statements is true?


$98\%$ of the boys studied in this survey grew between $2.8$ to $4.3$ inches.


We are $98\%$ confident that boys grew between $2.8$ to $4.3$ inches from the age of thirteen to fourteen.


We are $98\%$ confident that the average height that boys grew in this study was between $2.8$ to $4.3$ inches .


The average height a boy grew from the age of thirteen to fourteen was between $2.8$ to $4.3$ inches $98\%$ of the time.


We are $98\%$ confident the average height that boy grew from the ages of thirteen to fourteen was between $2.8$ to $4.3$ inches.