Four people make observations recorded in the table. Person
Georgina
Observation
A ball falls.
Amy
Bonds between atoms change
Wilhelm
Breaking the nucleus of an atom causes an
explosion
Heat moves from hot to cold areas.
Ron
Which best describes what all of the observations have in common?

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?