Question

Damage to grapes from bird predation is a serious problem for grape growers. An article reported on an experiment involving a bird-feeder table, time-lapse video, and artificial foods. Information was collected for two different bird species at both the experimental location and at a natural vineyard setting. Consider the following data on time (sec) spent on a single visit to the location. (Note: Assume the populations are normally distributed.)

Species		Location		n		x		SE mean
Blackbirds		Exptl		55		13.5		2.04
Blackbirds		Natural		45		9.9		1.77
Silvereyes		Exptl		33		49.5		4.76
Silvereyes		Natural		26		38.5		5.05

(a) Calculate an upper confidence bound for the true average time that blackbirds spend on a single visit at the experimental location. (Use α = 0.05. Round your answer to two decimal places.)

(b) Does it appear that true average time spent by blackbirds at the experimental location exceeds the true average time birds of this type spend at the natural location? Carry out a test of appropriate hypotheses. (Use α = 0.05.)

Compute the test statistic and P-value. (Round your test statistic to two decimal places and your P-value to three decimal places.)

t =
P-value =

(c) Estimate the difference between the true average time blackbirds spend at the natural location and true average time that silvereyes spend at the natural location, and do so in a way that conveys information about reliability and precision. (Use a 95% confidence interval for μ_silvereyes − μ_blackbirds. Use α = 0.05. Round your answers to two decimal places.)

Answer 1