/*! 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

For Exercises 1 to 4, identify the population, the parameter, the sample, and the statistic in each setting.

Gas prices How much do gasoline prices vary in a large city? To find out, a reporter records the price per gallon of regular unleaded gasoline at a random sample of 10gas stations in the city on the same day. The range (maximum-minimum) of the prices in the sample is 25cents

The California Department of Fish and Game publishes a list of the state鈥檚 endangered animals. The reptiles on the list are given across the bottom of the question.

(a) Describe how you would use Table D at line 111 to choose an SRS of 3 of these reptiles to study.

(b) Use your method from part (a) to select your sample. Identify the reptiles you chose.

Desert tortoise Green sea turtle Loggerhead sea turtle Giant garter snake Olive Ridley sea turtle Leatherback sea turtle Barefoot banded gecko San Francisco garter snake Island night lizard Alameda whip snake Coachella Valley fringe-toed lizard Flat-tailed horned lizard Southern rubber boa blunt-nosed leopard lizard

Suppose that you are a student aide in the library and agree to be paid according to the 鈥渞andom pay鈥� system. Each week, the librarian flips a coin. If the coin comes up heads, your pay for the week is \(80. If it comes up tails, your pay for the week is \)40. You work for the library for 100 weeks. Suppose we choose an SRS of 2 weeks and calculate your average earnings x. The shape of the sampling distribution of xwill be

(a) Normal.

(b) approximately Normal

(c) right-skewed

(d) left-skewed.

(e) symmetric but not Normal.

IQ tests The Wechsler Adult Intelligence Scale (WAIS) is a common "IQ test" for adults. The distribution of WAIS scores for persons over 16years of age is approximately Normal with mean 100 and standard deviation 15.

(a) What is the probability that a randomly chosen individual has a WAIS score of 105 or higher? Show your work.

(b) Find the mean and standard deviation of the sampling distribution of the average WAIS score x炉 for an SRS of 60 people.

(c) What is the probability that the average WAIS score of an SRS of 60 people is 105 or higher? Show your work.

(d) Would your answers to any of parts (a), (b), or (c) be affected if the distribution of WAIS scores in the adult population were distinctly non-Normal? Explain.

A sample survey interviews an SRS of 267college women. Suppose (as is roughly true) that 70%of college women have been on a diet within the past12months. What is the probability that 75%or more of the women in the sample have been on a diet? Follow the four-step process.
See all solutions

Recommended explanations on Math Textbooks

Theoretical and Mathematical Physics

Read Explanation

Probability and Statistics

Read Explanation

Geometry

Read Explanation

Statistics

Read Explanation

Calculus

Read Explanation

Decision Maths

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.