the amount of jens month phone bill is normally distributed with a mean of $69 and a standard deviation of $10. what is 68.26% of phone bill between?

1 answer

I just love this applet for this work, replaces all those nasty charts and tables in the back of text-books

http://davidmlane.com/hyperstat/z_table.html

click on "value from an area"
enter mean as 69
SD as 10
click on "between" to get
$59 and $79