1. Manning and Jasper (1984) studied bird foraging behavior in a forest in British Columbia. In a managed forest, 54% of the canopy volume wasDouglas fir, 28% wasponderosa pine, 5% wasgrand fir, and 1% waswestern larch. They made 156 observations of foraging byred-breasted nuthatches(birds); 70 observations (45% of the total) inDouglas fir, 79 (51%) inponderosa pine, 3 (2%) ingrand fir, and 4 (3%) inwestern larch.

What is the biological null hypothesis?Is the difference in proportion significant?Include the value of your calculated statistic, its degrees of freedomif any, and the calculated p-value in your answer.

2. A psychologist has developed a standardized test for measuring vocabulary skills in 4-year-old children. The scores on the test form a normal distribution with ? = 60 and ? = 10.A researcher would like to use this test to investigate the hypothesis that children who grow up as single children develop vocabulary skills at a faster rate than children in larger families.A sample of n = 25 single children is obtained, and a mean test score for this sample is X = 63.

Using a 95% Confidence Interval is there a difference between single children's vocabulary development and children from larger families' vocabulary development?

3. Students are given different drug treatments before revising for their exams.Some were given a memory drug, some a placebo drug and some no treatment.The exam scores(%) are shown below for the three different groups: