AG $505-$ Statistical Methods in Agriculture

Instructor: Dr$.$ Jose Lopez

You will work on this exam individually. That is$,$ you are neither allowed to discuss nor share

your answers with your classmates $($neither hard copies nor electronic versions of your answers$).$

If you do not understand the instructions provided in this assignment, you should contact your

instructor. You are required to submit your answers to this Exam in one Word document and

all supporting documentation in one Excel document via the Exam $3$ sub$-$tab in the

MyLeoOnline $($D$2$L$)$ website for the course. For those questions that you can only answer in

Excel $($such as when you create new sub$-$datasets$),$ make sure you write a note in your Word

document telling me where to find your answer in your Excel document.

In $2011$ researcher Wendie Clubine analyzed Texas elementary school principal's perceptions of school

gardening programs. She selected $110$ potential respondents eligible for participation in the study:

$35$ elementary school principals listed at the National Gardening Association and $75$ elementary school

principals listed at the Rainwater Educational Alliance for Learning. She mailed a pre$-$notice letter to all

$110$ potential respondents one week prior to emailing the first invitation. A week later, she emailed the

first invitation for participation to all elementary school principals with two hyperlinks included, one to

enter the questionnaire and one to opt out of the study. Two weeks later, she emailed a second invitation

to those principals who had not completed the questionnaire emphasizing the importance of their

contribution and the same two hyperlinks were included. Another two weeks later, she emailed a third

invitation to those principals who had not completed the questionnaire furthering stressing the importance

of their response. Forty five principals decided to take the survey; however, $1$ declined to participate in

the study and did not answer any further question while $4$ only answered selective questions. The Texas

Principals' School Garden dataset provided contains the principals' answers to selective questions from

Clubine $(2011).$ If you point to the variable names in the first row of the Excel document, you can read

the full questions via comments.

The sampling frame is a list, map, or other specification of sampling units in the population from

which a sample may be selected. Clubine's $(2011)$ sampling frame consisted of registry lists

available from the National Gardening Association and Rainwater Educational Alliance for Learning.

Defining the target population is an important and often difficult part of the study. The target

population is defined as the complete collection of observations the researcher wants to study. Figure

$1\mathrm{.}1$ summarizes the difference between sampling frame $($green and black boxes$),$ target population

$($blue box$),$ and sampled population $($black box$).$ Use Figure $1\mathrm{.}1.$ to carefully describe Clubine's

$(2011)$ target population. Make sure you explain the difference among Clubine's target population,

sampling frame, and the ultimate population that was sampled. $($Points: $4)$