/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q 62. More rain for California? The ch... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 4: Q 62. (page 255)

More rain for California? The changing climate will probably bring more rain to California, but we don鈥檛 know whether the additional rain will come during the

winter wet season or extend into the long dry season in spring and summer. Kenwyn Suttle of the University of California at Berkeley and his coworkers carried

out an experiment to study the effects of more rain in either season. They randomly assigned plots of open grassland to three treatments: added water equal to 20%of annual rainfall either during January to March (winter) or during April to June (spring), and no added water (control). Thirty-six circular plots of area 70square meters were available (see the photo), of which 18were used for this study. One response variable was total plant biomass, in grams per square meter, produced in a plot over a year.

(a) Outline the design of the experiment. What is this type of design called?

(b) Explain how you would randomly assign the experimental units to the three treatments. Then carry out your random assignment.

Short Answer

Expert verified

(a) This is totally randomized system.

(b) Allot corresponding numbers to plot, mix them we, Take out six, allocate group 1. Repeat the process till all are done.

Step by step solution

01

Given Information

To study the effect of more rains, plots re randomly assigned to three treatments.

They randomly assigned plots of open grassland to three treatments: added water equal to 20%of annual rainfall either during January to March (winter) or during April to June (spring), and no added water (control).

Eighteen among thirty six plots are used for study.

02

To identify type of design

The treatment are distributed by chance to all units in strict randomized system. The system is strictly randomized system.

The description is:

03

To explain random assignment of groups to three treatments.

  • For 18plots, assign numbers from 1-18in paper slips.
  • Mix it in utensil and take out six pieces. Allocate them group1
  • Draw six again and allocate them group 2.
  • Repeat the step again and allocate group 3.
  • Compare total biomass produced in three groups after one year.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Sampling the forest To gather data on a 1200-acre pine forest in Louisiana, the U.S. Forest Service laid a grid of 1410 equally spaced circular plots over a map

of the forest. A ground survey visited a sample of 10% of these plots.12

(a) Explain how you would use technology or Table D to choose an SRS of 141 plots. Your description should be clear enough for a classmate to obtain your results.

(b) Use your method from (a) to choose the first 3 plots.

A simple random sample of 1200 adult Americans is selected, and each person is asked the following question: 鈥淚n light of the huge national deficit, should the government at this time spend additional money to establish a national system of health insurance?鈥� Only 39% of those responding answered 鈥淵es.鈥� This survey

(a) is reasonably accurate since it used a large simple random sample.

(b) needs to be larger since only about 24 people were drawn from each state.

(c) probably understates the percent of people who favor a system of national health insurance.

(d) is very inaccurate but neither understates nor overstates the percent of people who favor a system of national health insurance. Since simple random sampling was used, it is unbiased.

(e) probably overstates the percent of people who favor a system of national health insurance.

Headache relief Doctors identify 鈥渃hronic tension- type headaches鈥� as headaches that occur almost daily for at least six months. Can antidepressant medications or stress management training reduce the number and severity of these headaches? Are both together more effective than either alone? Investigators compared four treatments: antidepressant alone, placebo alone, antidepressant plus stress management, and placebo plus stress management. The headache sufferers named in the following table have agreed to participate in the study.

(a) Outline the design of the experiment. What is this type of design called?

(b) Explain how you would randomly assign the subjects to the four treatment groups. Then carry out your random assignment.

Effects of binge drinking A common definition of 鈥渂inge drinking鈥� is 5 or more drinks at one sitting for men and 4 or more for women. An observational study

finds that students who binge drink have lower average GPA than those who don鈥檛. Identify a lurking variable that may be confounded with the effects of binge drinking. Explain how confounding might occur.

Sampling frame Ideally, the sampling frame in a sample survey should list every individual in the population, but in practice, this is often difficult.

Suppose that a sample of households in a community is selected at random from the telephone directory. Explain how this sampling method results in under coverage that could lead to bias.
See all solutions

Recommended explanations on Math Textbooks

Logic and Functions

Read Explanation

Geometry

Read Explanation

Theoretical and Mathematical Physics

Read Explanation

Discrete Mathematics

Read Explanation

Applied Mathematics

Read Explanation

Probability and Statistics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.