2 histograms, the first titled 1960 and the second titled 2010. The Y-axis of each histogram is labeled Number of Birds, and the X-axis is labeled Beak Length in intervals from 1 to 10, with 1 labeled Short and 10 labeled Long. The height of the bars in the first histogram ascends and descends evenly from 1 to 10, peaking at 5 and 6. The height of the bars in the second histogram also ascends and descends evenly from 3 to 8, peaking at 5 and 6, with no bars at 1, 2, 9, and 10. The tallest bars in the second histogram rise more than twice as high as the tallest bars in the first histogram.

Question

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18. Scientists measured the beak length of a population of birds in a lake in 1960. They measured the beak length of the bird population again in 2010. What do the graphs show you about the variation in the beak lengths of the birds by the lake?
Responses

a
There was the same amount of variation in 1960 and in 2010.
There was the same amount of variation in 1960 and in 2010.

b
These bar graphs do not show the amount of variation in the population.
These bar graphs do not show the amount of variation in the population.

c
There was more variation in 2010.
There was more variation in 2010.

d
There was more variation in 1960.

Answer 1

The correct response is:

d There was more variation in 1960.

This conclusion is drawn from the first histogram, which shows a distribution of beak lengths that ascends and descends evenly across the range, indicating a wider variation in beak lengths (1 to 10). In contrast, the second histogram (2010) shows a more limited range of beak lengths, with significant gaps (no measurements for 1, 2, 9, and 10), indicating reduced variation in beak lengths compared to 1960.