Question

Data is collected on the frequency of mountain bird songs at three different elevations. Data is collected from 100 birds at each elevation.

Low altitude: 80 below 1500 Hz
Medium altitude: 50 below 1500 Hz
High altitude: 20 below 1500 Hz

How does altitude relate to song frequency of birds?

(1 point)
Responses

Altitude does not affect bird song frequencies.
Altitude does not affect bird song frequencies.

Medium altitude has medium frequency songs.
Medium altitude has medium frequency songs.

Higher altitudes are correlated with higher song frequencies.
Higher altitudes are correlated with higher song frequencies.

Higher altitudes are correlated with lower song frequencies.

Answer 1

Higher altitudes are correlated with higher song frequencies.

Justification: the proportion of birds below 1500 Hz decreases from 80% (low) to 50% (medium) to 20% (high), so the fraction singing above 1500 Hz increases with altitude.