Question

In: Statistics and Probability

1.Suppose that an animal behaviorist is concerned about the effects of a nearby freeway on the...

1.Suppose that an animal behaviorist is concerned about the effects of a nearby freeway on the nesting behavior of an endangered bird. In this fictional study, suppose that nesting behavior is measured by counting the number of trips to the nest per hour for an individual bird. The animal behaviorist compares a random sample of 40 birds nearby the freeway to a random sample of 40 birds in an undisturbed location. For 24 weeks, the animal behaviorist sets up cameras to count the number of trips to the nest per hour for each bird.

At the end of the 24-week period, the animal behaviorist compares the mean number of trips to the nest per hour for the freeway location and the undisturbed location. The animal behaviorist is using a 5% significance level. The mean number of trips to the nest per hour is less for the birds at the freeway location. The differences are statistically significant at the 4% level.

What conclusion can we draw from these results?

A. The animal behaviorist has proven that nearby freeways cause endangered birds to make less trips per hour to their nests.

B. There is a large difference in the counts of nesting trips for birds in the two groups.

C. There is evidence that nearby freeways may contribute to a change in nesting behavior but the study design prohibits a cause-and-effect conclusion.

D. The sample size is too small to draw a valid conclusion.

2. Weight of a rock: In a geology course, students are learning to use a balance scale to accurately weigh rocks. One student plans to weigh a rock 20 times and then calculate the average of the 20 measurements to estimate her rock's true weight. A second student plans to weigh a rock 5 times and calculate the average of the 5 measurements to estimate his rock's true weight.

The student who weighs his rock 5 times uses the mean to calculate the 95% confidence interval for the rock weight (in grams). His interval is (25.2, 29.1). What does a 95% confidence interval for rock weight tell us in this case?

A.We are 95% confident that this interval includes the mean of the 5 weight measurements taken by this student.

B.We are 95% confident that most rocks of this type weigh between 25.2 g and 29.1 g.

C.We are 95% confident that the true weight of the rock is between 25.2 g and 29.1 g.

3. A medical researcher wants to measure the effects of a new drug on cholesterol levels using a hypothesis test. The target is a 30-point decrease in cholesterol levels after a treatment cycle. The researcher takes a random sample of patients and measures their cholesterol levels before and after a treatment cycle of the drug.

Which type of hypothesis test should they use?

A.test for one population proportion

B.test for one population mean

C.test for a difference in two population proportions

D.test for a difference in two population means

Solutions

Expert Solution

1. Answer-

C is correct option..there is evedence that nearby freeway may contribute to change in nesting behaviour.

This is due to the fact that the difference is statistically significant at 4 % level of significance that means we are 96% sure that the average trip to the best per hour is less than the average that of birds at freeway this suggests that there is slightly change in the behaviour of nesting of undisturbed birds.

2) weight of rock

Answer- C is correct option

As the interval of students who weigh rock five times is between (25.9,29.1) this means that there is 95 % chance that the true weight of the rock must be lie in between the two interval i.e. between 25.9 to 29.1

3 ) B option is correct.

As here the researcher is taking random sample of patients and measure the cholesterol level before and after the treatment cycle of drug.here the population will remains same for the bother sample i.e. before treatment or after treatment so, here is the case of testing of paired means .so here population is one..


Related Solutions

A animal behaviorist wants to know how exercise affects behavior of aggressive dogs. She finds a...
A animal behaviorist wants to know how exercise affects behavior of aggressive dogs. She finds a sample of 30 aggressive dogs and randomly divides them into three groups. Over one week, one group is exercised for 20 minute per day, one for one hour per day, and one for 2 hours per day. The number of aggressive behaviors (lunging, biting, snarling, etc.) is recorded for the dogs in each group. State the population(s) of interest. Identify the parameter(s) of interest....
Martha lives near a paper mill. If she is concerned about the effects of the air...
Martha lives near a paper mill. If she is concerned about the effects of the air pollution from the plant, she should contact which regulatory agency? a. Consumer Product Safety Commission (CPSC) b. Occupational Safety and Health Administration (OSHA) c. Food and Drug Administration (FDA) d. Environmental Protection Agency (EPA) Which of the following statements is true? a. Deficient information on unsafe products causes underconsumption. b. The rule of reason doctrine declares that the existence of monopoly alone is illegal....
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company...
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company sells 70,000 units for $55 per unit. The variable production costs are $30, and fixed costs amount to $800,000. Production engineers have advised management that they expect unit labor costs to rise by 20 percent and unit materials costs to rise by 5 percent in the coming year. Of the $30 variable costs, 60 percent are from labor and 15 percent are from materials....
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company...
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company sells 61,000 units for $35 per unit. The variable production costs are $20, and fixed costs amount to $710,000. Production engineers have advised management that they expect unit labor costs to rise by 15 percent and unit materials costs to rise by 10 percent in the coming year. Of the $20 variable costs, 40 percent are from labor and 20 percent are from materials....
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company...
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company sells 72,000 units for $40 per unit. The variable production costs are $25, and fixed costs amount to $820,000. Production engineers have advised management that they expect unit labor costs to rise by 15 percent and unit materials costs to rise by 10 percent in the coming year. Of the $25 variable costs, 60 percent are from labor and 30 percent are from materials....
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company...
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company sells 66,000 units for $35 per unit. The variable production costs are $20, and fixed costs amount to $760,000. Production engineers have advised management that they expect unit labor costs to rise by 20 percent and unit materials costs to rise by 15 percent in the coming year. Of the $20 variable costs, 45 percent are from labor and 30 percent are from materials....
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company...
Argentina Partners is concerned about the possible effects of inflation on its operations. Presently, the company sells 79,000 units for $30 per unit. The variable production costs are $15, and fixed costs amount to $890,000. Production engineers have advised management that they expect unit labor costs to rise by 20 percent and unit materials costs to rise by 15 percent in the coming year. Of the $15 variable costs, 40 percent are from labor and 20 percent are from materials....
Suppose that consumers are concerned about theft, and so they are willing to use banks for...
Suppose that consumers are concerned about theft, and so they are willing to use banks for some of their transactions even if the nominal interest rate is zero. Further, suppose that, the more currency consumers hold, the more people are encouraged to steal, as theft is now more profitable. How would the Friedman rule for monetary policy be altered under these circumstances?
Suppose that the two approaches to a freeway merge, labelled 1 and 2, have individual capacities...
Suppose that the two approaches to a freeway merge, labelled 1 and 2, have individual capacities of 2000 veh/h and 6000 veh/h, respectively. Suppose that the two approaches can send a combined maximum flow 6000 veh/h through the merge without queues forming. Suppose as well that if both approaches are queued, vehicles enter the merge in a 1:3 ratio; i.e., three vehicles from approach 2 for each vehicle from approach 1. At t = 0, there are no queues in...
Suppose you’re building a vacation cottage up in the Rocky Mountains and you are concerned about...
Suppose you’re building a vacation cottage up in the Rocky Mountains and you are concerned about the depth at which a new water line should be buried to avoid freezing during the cold winter weather. The soil there is dry and homogenous with a thermal diffusivity of 0.02 ft2/hr and a thermal conductivity of0.48 Btu/ ft hr °F . Suppose the initial temperature is 45 °F everywhere. At t=0, a very strong cold front moves in and the ambient temperature...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT