Blue titmice eat caterpillars. The birds would like lots of caterpillars around

Question

Blue titmice eat caterpillars. The birds would like lots of caterpillars around when they have young to feed, but they breed earlier than peak caterpillar season. Do the birds learn from one year's experience when they time breeding the next year? Researchers randomly assigned 7 pairs of birds to have the natural caterpillar supply supplemented while feeding their young and another 6 pairs to serve as a control group relying on natural food supply. The next year, they measured how many days after the caterpillar peak the birds produced their nestlings. The investigators expected the control group to adjust their breeding date the next year, whereas the well-fed supplemented group had no reason to change. The report continues: "but in the following year food-supplemented females were more out of synchrony with the caterpillar peak than the controls." Here are the data (days behind the caterpillar peak).

Control 4.5 2.5 7.0 5.9 5.2 -0.9
Supplemented 16.4 10.8 5.9 16.8 12.0 10.7 6.5

Carry out a t test and show that it leads to the quoted conclusion. (Use degrees of freedom equal to the smaller of n1 1 and n2 1. Use = 0.05. Round your test statistic to three decimal places and your P-value to four decimal places.)

t = ?
P-value = ?

Conclusion (choose 1)
Food-supplemented females were more out of synchrony with the caterpillar peak than the controls.

There is no difference between groups between synchrony with the caterpillar peak.  

Explanation / Answer

Blue titmice eat caterpillars. The birds would like lots of caterpillars around

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