The Normal Distribution Practice Test

For the population of all adult male heights in a region, heights are approximately Normal with mean $\mu=69$ inches and standard deviation $\sigma=3$ inches. A normal curve is shown with the value $63$ inches marked.

  Normal curve (height)
  |
  |                 .-''''-.
  |              .-'        '-.
  |            .'              '.
  |           /                  \
  |----------|----|----|----|----|----|----|----> x
            60   63   66   69   72   75   78
                 63      $\mu=69$

Which statement about the marked value is correct?

The lifetimes of a certain brand of light bulb (population of all bulbs of this brand) are approximately Normal with mean $\mu=1200$ hours and standard deviation $\sigma=150$ hours. A normal curve is shown with the value $1050$ hours marked.

  Normal curve (hours)
  |
  |                 .-''''-.
  |              .-'        '-.
  |            .'              '.
  |           /                  \
  |----------|----|----|----|----|----|----|----> x
           750  900  1050 1200 1350 1500 1650
                     <u>1050</u>  \mu=1200

Which statement about the marked value is correct?