Moderate# Dr. Doolittle and the Giraffes: Conclusions from a Test

APSTAT-VUIEYN

Dr. Doolittle was looking through his old textbooks and found one that said the average height of an adult male giraffe is $18$ feet with a standard deviation of $1.1$ feet. He sees many giraffes and wonders if this average is true. To check it out, he selects the records of $40$ adult male giraffes that come to see him, records their height and finds the sample average to be $18.35$ feet.

Assuming that he is willing to consider his sample to represent a random sample, what conclusion would Dr. Doolittle reach after conducting an appropriate statistical test?