/*! 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. 24 AP2.24. Every 17聽years, swarms ... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 7: Q. 24 (page 465)

AP2.24. Every 17years, swarms of cicadas emerge from the ground in the eastern United States, live for about six weeks, and then die. (There are several different 鈥渂roods,鈥� so we experience cicada eruptions more often than every 17years.) There are so many cicadas that their dead bodies can serve as fertilizer and increase plant growth. In a study, a researcher added 10cicadas under 39randomly selected plants in a natural plot of American bell flowers on the forest floor, leaving other plants undisturbed. One of the response variables measured was the size of seeds produced by the plants. Here are the box plots and summary statistics of seed mass (in milligrams) for 39cicada plants and 33undisturbed (control) plants:

Variable: n Minimum Q1 Median Q3 Maximum

Cicada plants: 39 0.17 0.22 0.25 0.28 0.35
Control plants: 33 0.14 0.19 0.25 0.26 0.29
(a) Is this an observational study or an experiment? Explain.
(b) Based on the graphical displays, which distribution has
the larger mean? Justify your answer.
(c) Do the data support the idea that dead cicadas can
serve as fertilizer? Give graphical and numerical evidence
to support your conclusion.

Short Answer

Expert verified

(a) The given study is an experimental study.

(b) The given data concluded that the mean of the cicada plants is larger.

(c) The data is not supporting the belief that dead cicadas could be served as fertilizer. Because, the median for both the groups is same.

Step by step solution

01

Part (a) Step 1: Given information 

In a study, a researcher added 10cicadas under 39 randomly selected plants in a natural plot of American bell flowers on the forest floor, leaving other plants undisturbed.

02

Part (a) Step 2: Explanation

A study in which an experimenter or researcher handles the situation is understood as an experimental study.
The experimental study has full control over, which proceeding into the plot of the land.
Hence, the given study is an experimental study.

03

Part (b) Step 1: Given information 

The box plots and summary statistics of seed mass (in milligrams) for 39cicada plants and 33 undisturbed (control) plants.

04

Part (b) Step 2: Explanation 

The mean is strongly influenced by skewness, the mean is more influenced by the left-skewness in the control plants distribution.

Since a left-skewed distribution containing the smaller value thus it would reduce the mean .

So, it could be concluded that the mean of the cicada plants is larger.

05

Part (c) Step 1: Given information 

To conclude the data is supporting the belief that dead cicadas could be served as fertilizer.

06

Part (c) Step 2: Explanation 

From the given figure and numerical summaries of , it is known that the the median for cicada and control groups are same, that is 0.25.

The data is not supporting the belief that dead cicadas could be served as fertilizer. Because, the median for both the groups is same.

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

You want to take an SRS 50of the 816students who live in a dormitory on a college campus. You label the students 001to 816in alphabetical order. In the table of random digits, you read the entries

95592 94007 69769 33547 72450 16632 81194 14873

The first three students in your sample have labels

(a) 955,929,400

(b) 400,769,769

(c) 559,294,007

(d) 929,400,769

(e) 400,769,335

Scooping beads A statistics teacher fills a large container with 1000white and 3000red beads and then mixes the beads thoroughly. She then has her students take repeated SRSs of 50beads from the container. After many SRSs, the values of the sample proportion p藛 of red beads are approximated well by a Normal distribution with mean of 0.75and standard deviation of 0.06.

(a) What is the population? Describe the population distribution. (b) Describe the sampling distribution of p藛. How is it different from the population distribution?

Songs on an iPod David's iPod has about 10000songs. The distribution of the play times for these songs is heavily skewed to the right with a mean of 225seconds and a standard deviation of 60seconds. How many songs would you need to sample if you wanted the standard deviation of the sampling distribution of x炉to be30seconds? justiify your answer.

Squirrels and their food supply (3.2) Animal species produce more offspring when their supply of food goes up. Some animals appear able to anticipate unusual food abundance. Red squirrels eat seeds from pinecones, a food source that sometimes has very large crops. Researchers collected data on an index of the abundance of pinecones and the average number of offspring per female over 16years. Computer output from a least-squares regression on these data and a residual plot.

(a) Give the equation for the least-squares regression line. Define any variables you use.

(b) Explain what the residual plot tells you about how well the linear model fits the data.

(c) Interpret the values of r2and s in context.

You work for an advertising agency that is preparing a new television commercial to appeal to women. You have been asked to design an experiment to compare the effectiveness of three versions of the commercial. Each subject will be shown one of the three versions and then asked about her attitude toward the product. You think there may be large differences between women who are employed and those who are not. Because of these differences, you should use

(a) a block design, but not a matched pairs design

(b) a completely randomized design.

(c) a matched pairs design.

(d) a simple random sample.

(e) a stratified random sample.

See all solutions

Recommended explanations on Math Textbooks

Decision Maths

Read Explanation

Probability and Statistics

Read Explanation

Mechanics Maths

Read Explanation

Statistics

Read Explanation

Calculus

Read Explanation

Applied Mathematics

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.