Question

Mr. Wilder has a reputation for holding his classes for a few minutes after the bell has rung at the end of the period. In fact, it seems he ends class according to his own “internal clock.” Below is a density curve that describes the distribution of times when Mr. Wilder end his class, where negative values are minutes before the bell rings and positive values are minutes after the bell rings. What proportion of time does Mr. Wilder end class within one minute of when the bell went off? Shade the appropriate area on the graph to show how you found the answer.