/*! 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. 13 Lamb鈥檚-quarter is a common wee... [FREE SOLUTION] | 91影视

91影视

Lamb鈥檚-quarter is a common weed that interferes with the growth of corn. An agriculture researcher planted corn at the same rate in 16small plots of ground and then weeded the plots by hand to allow a fixed number of lamb鈥檚-quarter plants to grow in each meter of the cornrow. The decision of how many of these plants to leave in each plot was made at random. No other weeds were allowed to grow. Here are the yields of corn (bushels per acre) in each of the plots.

Weedsper meterCorn yieldWeedsper meterCorn yield0166.73158.60172.23176.40165.03153.10176.93156.01166.29162.81157.39142.41166.79162.81161.19162.4

(a) A scatterplot of the data with the least-squares line added is shown below. Describe what this graph tells you about the relationship between these two variables.

Minitab output from a linear regression on these data is shown below

PredictorCoefSE CoefTPConstant166.4832.72561.110.000Weeds permeter-1.09870.5712-1.920.075

S=7.97665R-Sq=20.9%R-Sq(adj)=15.3%

(b) What is the equation of the least-squares regression line for predicting corn yield from the number of lamb鈥檚 quarter plants per meter? Define any variables you use.

(c) Interpret the slope and y-intercept of the regression line in context.

(d) Do these data provide convincing evidence that more weeds reduce corn yield? Carry out an appropriate test at the A =0.05level to help answer this question.

Short Answer

Expert verified

(a) The scatterplot indicates that the variables have a weak negative linear connection.

(b) The equation is y^=166.483-1.0987x.

(c) Slope: Corn yields are predicted to drop by1.0987bushels per weed per meter this year.

Intercept: When there are0weeds per meter, the corn yield is estimated to be166.483.

(d) Yes, there is enough evidence to back up the notion that more weeds lower maize production.

Step by step solution

01

Part(a) Step 1: Given Information

02

Part(a) Step 2: Explanation

The researcher looked at the weeds among the crop yields in the query. As a result, the scatterplot for the variables utilized is also included in the question. As a result, we can deduce from the scatterplot that

Because the scatterplot slopes downhill, the direction is negative.

Because the points appear to nearly lie along a line, the form is linear.

Because the points are so wide apart, the strength is weak.

03

Part(b) Step 1: Given Information

Minitab output from a linear regression on these data is shown below PredictorCoefSE CoefTPConstant166.4832.72561.110.000Weeds permeter-1.09870.5712-1.920.075

S=7.97665R-Sq=20.9%R-Sq(adj)=15.3%

04

Part(b) Step 2: Explanation

Now, we know that the researcher evaluated weeds among corn yields in the inquiry, and the computer output of this data is provided. Also, the generic regression equation is as follows:

y^=a+bx

In the "Coef" column of the computer output, the estimates aand bare given:

y^=a+bx=166.483-1.0987x

y^represents the expected corn yield, and xrepresents the number of weeds per meter.

05

Part(c) Step 1: Given Information

Minitab output from a linear regression on these data is shown below.

PredictorCoefSE CoefTPConstant166.4832.72561.110.000Weeds permeter-1.09870.5712-1.920.075

S=7.97665R-Sq=20.9%R-Sq(adj)=15.3%

06

Part(c) Step 2: Explanation

Now, we know that the researcher evaluated weeds among corn yields in the inquiry, and the computer output of this data is provided. As we all know, the general regression equation is as follows:

y^=a+bx

In the "Coef" column of the computer output, the estimates aand bare given:

y^=a+bx=166.483-1.0987x

y^represents the expected corn yield, and xrepresents the number of weeds per meter.

The coefficient of xis thus -1.0987, and the slope bis thus-1.0987.

And the y-intercept an is the regression equation's constant, resulting in166.483.

07

Part(d) Step 1: Given Information

Minitab output from a linear regression on these data is shown below.

PredictorCoefSE CoefTPConstant166.4832.72561.110.000Weeds permeter-1.09870.5712-1.920.075

S=7.97665R-Sq=20.9%R-Sq(adj)=15.3%

08

Part(d) Step 2: Explanation

The following is taken from the computer output:

n=16b=-1.0987SEb=0.5712

As a result, we define the hypothesis as follows:

H0:=0

Ha:<0

As a result, the test statistics have the following value:

t=b-SEb=-1.0987-00.5712=-1.923

The degrees of freedom are as follows:

df=n-2=16-2=14

As a result, the p-value is:

0.025<P<0.05

Alternatively, the p-value can be calculated using technology as follows:

P=0.03753

The null hypothesis is rejected if the p-value is less than or equal to the significance level, as follows:

P<0.05RejectH0

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

Students in a statistics class drew circles of varying diameters and counted how many Cheerios could be placed in the circle. The scatterplot shows the results.

The students want to determine an appropriate equation for the relationship between diameter and the number of Cheerios. The students decide to transform the data to make it appear more linear before computing a least-squares regression line. Which of the following single transformations would be reasonable for them to try?

I. Take the square root of the number of Cheerios.

II. Cube the number of Cheerios.

III. Take the log of the number of Cheerios.

IV. Take the log of the diameter.

(a) I and II

(b) I and III

(c) II and III

(d) II and IV

(e) I and IV

The body鈥檚 natural electrical field helps wounds heal. If diabetes changes this field, it might explain why people with diabetes heal more slowly. A study of this idea compared randomly selected normal mice and randomly selected mice bred to spontaneously develop diabetes. The investigators attached sensors to the right hip and front feet of the mice and measured the difference in electrical potential (in millivolts) between these locations. Graphs of the data for each group reveal no outliers or strong skewness. The computer output below provides numerical summaries of the data26.

The researchers want to know if there is evidence of a significant difference in mean electrical potentials between normal mice and mice with diabetes. Carry out a test using a 5%level of significance and report your conclusion.

A large machine is filled with thousands of small

pieces of candy, 40%of which are orange. When money

is deposited, the machine dispenses 60randomly selected

pieces of candy. The machine will be recalibrated if a

group of 60candies contains fewer than18 that are

orange. What is the approximate probability that this will

happen?

a)Pz<0.3-0.4(0.4)(0.6)60

b)Pz<0.4-0.3(0.3)(0.7)60

role="math" localid="1650519113387" c)Pz<0.3-0.4(0.4)(0.6)60

role="math" localid="1650519757907" d)Pz<0.3-0.4(0.4)(0.6)60

e)Pz<0.4-0.3(0.3)(0.7)60

Beavers and beetles Do beavers benefit beetles? Researchers laid out 23 circular plots, every four meters in diameter, at random in an area where beavers were cutting down cottonwood trees. In each plot, they counted the number of stumps from trees cut by beavers and the number of clusters of beetle larvae. Ecologists think that the new sprouts from stumps are more tender than other cottonwood growth so beetles prefer them. If so, more stumps should produce more beetle larvae.

Minitab output for a regression analysis on these data is shown below. Construct and interpret a 99% confidence interval for the slope of the population regression line. Assume that the conditions for performing inference are met.

Insurance adjusters are always vigilant about being overcharged for accident repairs. The adjusters suspect that Repair Shop 1quotes higher estimates than Repair Shop 2. To check their suspicion,

the adjusters randomly select 12cars that were recently involved in an accident and then take each of the cars to both repair shops to obtain separate estimates of the cost to 铿亁 the vehicle. The

estimates are given below in hundreds of dollars.


Assuming that the conditions for inference are reasonably met, which of the following signi铿乧ance tests could legitimately be used to determine whether the adjusters鈥 suspicion is correct?

I. A paired ttest

II. A two-sample ttest

III. A t test to see if the slope of the population regression line is 0.

(a) I only

(b) II only

(c) I and III

(d) II and III

(e) I, II, and III

See all solutions

Recommended explanations on Math Textbooks

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.