4.60 ● Although bats are not known for their eyesight, they are able to locate prey (mainly insects) by emitting high-pitched sounds and listening for echoes. A paper appearing in Animal Behaviour (“The Echolocation of Flying Insects by Bats” [1960]: 141–154)

gave the following distances (in centimeters) at which a bat first detected a nearby insect:

62 23 27 56 52 34 42 40 68 45 83

a. Compute the sample mean distance at which the bat first detects an insect.

b. Compute the sample variance and standard deviation for this data set. Interpret these values.