Higher Vertebrates (Mammals and Birds) Exhibit Lateralized Behaviors, Commonly Referred

Essay

Higher vertebrates (mammals and birds) exhibit lateralized behaviors, commonly referred
to as "handedness." Recently an investigator studied the coiling behavior of the
Agkistrodon piscivorus leucostoma - more commonly known as the cottonmouth snake.
The cottonmouth is a venomous snake that spends much of its time in a coil, sometimes
coiled in a counter-clockwise direction, other times in a clockwise direction. The
investigator made many observations of coiling behavior, and calculated a "laterality
index" for 30 cottonmouths. He defined the laterality index for each snake as the
percentage of observations of the snake that were categorized as coils in the counter-
clockwise direction. In the table below the data on laterality has been separated into two
groups: females and males. $\begin{array}{l}\text { Laterality: Females }\\\begin{array}{|l|l|l|l|l|l|l|l|l|l|}\hline 58 & 55 & 61 & 54 & 64 & 60 & 42 & 49 & 56 & 42 \\\hline 59 & 55 & 55 & 60 & 66 & 70 & 49 & 51 & 57 & 43 \\\hline\end{array}\end{array}$


$\begin{array}{l}\text { Laterality: Males }\\\begin{array}{|c|c|c|c|c|c|c|c|c|c|}\hline 56 & 56 & 52 & 54 & 40 & 49 & 49 & 48 & 46 & 49 \\\hline\end{array}\end{array}$
-Calculate the values of these numerical summaries for the laterality index for the
sample of male cottonmouths: a) The mean __________
b) The standard deviation __________ The table below presents some summary statistics from the distribution of laterality index
of males and females. Partial summary of data
Laterality index
$\begin{array}{|c|c|c|c|c|c|}\hline \text { Age } & \text { Minimum } & \begin{array}{c}\text { Lower } \\\text { Quartile }\end{array} & \text { Median } & \begin{array}{c}\text { Upper } \\\text { Quartile }\end{array} & \text { Maximum } \\\hline \text { Females } & 42 & 50 & 55.5 & 60 & 70 \\\text { Males } & 40 & 48 & 49 & 54 & 56 \\\hline\end{array}$