Given
mean = 84 pounds
standar deviation = 13 pounds
Procedure
a. New hippo weighs between 90 and 109 pounds
Areas under portions of a normal distribution can be computed by using calculus. Since this is a non-mathematical treatment of statistics, we will rely on computer programs and tables to determine these areas.
[tex]\begin{gathered} \mu=84 \\ \sigma=13 \\ \end{gathered}[/tex]
Between 90 and 109
Results:
Area (probability) = 0.295
b. What weight corresponds with the 6th percentile?
The score you have entered means that the hippo is at the sixth percentile – their percentile rank is 6%
Given P(xZ = -1.555
The value of the z-score tells you how many standard deviations you are away from the mean.
[tex]\begin{gathered} z=\frac{x-\mu}{\sigma} \\ x=z\sigma+\mu \\ x=-1.555\cdot13+84 \\ x=63.785 \end{gathered}[/tex]
63.785 is the weight for the 6th percentile
c. What percentages of hippos are born weighing 27 pounds or less?
Z = (27 - 84)/13
Z-score = -4.38462
0% of hippos are born at 27 pounds or less
