Question:

Community ecologists draw "food webs" to describe the predator and prey relationships between all organisms living in an area. A theoretical model predicts that a measure of the structure of food webs called "diet discontinuity" should be zero. Diet discontinuity is a measure of the relative numbers of predators whose prey are not ordered contiguously. Researchers have measured discontinuity scores for seven different food webs in nature. The values are: 0.35, 0.08, 0.004, 0.08, 0.32, 0.28, 0.17. Assume discontinuity in natural food webs has a normal distribution. Are the results significantly different from the theoretical expectation? Answer TRUE for 'yes' and FALSE for 'no'.

True

False

2.As the world warms, geographic ranges of species might shift toward cooler areas. In the file 'RangeShiftsWithClimateChange.csv' are data from a study on the highest elevations at which species occur. Typically, higher elevations are cooler than lower elevations. The aforementioned file contains data in the changes in highest elevation for 31 taxa in meters between the late 1990's and the early 2000's. Positive numbers indicate upward shifts in elevation and negative numbers indicate shifts to lower elevations. Based on this information, the mean altitude shift is , the lower 95% confidence limit is , and the upper 95% confidence limit is . Please round your answers to zero decimal places (i.e., only provide rounded numbers to the left of where the decimal point would go).

3.Assume that Z is a number randomly chosen from a standard normal distribution. Use R to calculate P[Z

4.The babies born in singleton births in the United States have birth weights that are approximately normally distributed with mean 3.296 kg and standard deviation 0.560 kg. What is the probability of a newborn weighing between 3 and 4 kg? Round your answer to two decimal places.

5.It was rumored that Britain's domestic intelligence service, MI5, has an upper limit on the height of its spies, on the assumption that tall people stand out. The rumor also said that to be a spy, you could be no taller than 5 feet 11 inches (180.3 cm) if you are a man. If the true mean height of men in Britain is 177 cm and the true standard deviation is 7.1 cm, what fraction of men would be precluded from applying to MI5? Please round your answer to two decimal places.

6.Can a human swim faster in water or in syrup? It is unknown whether the increase in the friction of the body moving through syrup is compensated by the increased power of each stroke. The results of an experiment in which researchers filled one pool with water mixed with syrup and another with normal water are in the file 'SyrupSwimming.csv'. The data are presented as the relative speed of each swimmer in syrup (i.e., speed in syrup / speed in water). If syrup has no effect on swimming, the mean should be one. Assuming these data are normally distributed, use this information to test the null hypothesis that syrup has no effect on swim peed. Answer TRUE if syrup does have a statistically significant effect and FALSE if the test fails to reject the null hypothesis.

Question 4 1 pts The term R refers to O The R-square statistic evaluated at the kth observation in the data. O The sum of the residuals obtained by regressing the kth explanatory variable on all other explanatory variables. O An R-square statistic obtained by regressing the kth explanatory variable on all other explanatory variables. O The adjusted R-square statistic.Question 5 Consider the multivariate model: y = Bo + 8101 + 822 + u. If @1 and *2 are highly correlated, then the model may suffer from endogeneity O failure of the Gauss-Markov assumptions O multicollinearity O heteroskedasticity