/*! 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} Problem 95 Select the best answer Corn var... [FREE SOLUTION] | 91Ó°ÊÓ

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Select the best answer Corn variety 1 yielded 140 bushels per acre last year at a research farm. This year, corn variety 2, planted in the same location, yielded only 110 bushels per acre. Unfortunately, we don’t know whether the difference is due to the superiority of variety 1 or to the effect of this year’s drought. This is an example of (a) bias. (b) matched pairs design. (c) confounding. (d) the placebo effect. (e) replication.

Short Answer

Expert verified
The correct answer is (c) confounding.

Step by step solution

01

Understand the Context

We are examining two corn varieties and their yield in bushels per acre over two consecutive years. Corn variety 1 yielded 140 bushels per acre last year, while corn variety 2 yielded 110 bushels per acre this year. The conditions differ between the years because the second year had a drought.
02

Identify the Variables

There are two main variables: the type of corn variety and the environmental condition (drought). The outcome, or the variable of interest, is the yield of bushels per acre. These variables can influence the yield independently or together.
03

Recognize the Problem

We cannot determine whether the difference in yield is due to the corn variety's effectiveness or the environmental conditions, specifically the drought. This uncertainty complicates our ability to draw a clear conclusion about the advantage of one corn variety over the other.
04

Define Confounding

Confounding occurs when the effect of one variable on the response variable cannot be separated from the effect of another variable. In this scenario, the variable 'corn variety' is confounded with the variable 'drought year'. We cannot tell if the yield difference is due to the varieties themselves or due to the drought.
05

Select the Best Answer

Based on the situation and recognizing that there is an interaction between corn variety and environmental conditions affecting the outcome, the best term that describes this situation is confounding.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Confounding Variable
In statistical analysis, a confounding variable is one that confuses the relationship between the dependent and independent variables. This happens when you cannot distinctly attribute the observed effect to either one of the suspected variables.
In our corn example, the role of "drought" as a variable makes it unclear whether the differences in yield are due only to the type of corn or the environmental condition (drought) that occurred in the second year.
When you encounter confounding variables, it becomes challenging to make precise conclusions since these confounders distort the real effect of the variables under study. Clearly identifying and accounting for confounding variables is essential to improve the validity of study results.
Experimental Design
Experimental design is a structured approach to testing hypotheses in systematic studies. It involves planning how to gather data, deciding what kind of data to gather, and determining how to analyze this data.
In our context, if we want to test the effectiveness of different corn varieties, a proper experimental design might include:
  • Randomly assigning corn types to different plots to minimize the effect of confounding variables like drought.
  • Using control plots without any corn or with a neutral variety to measure baseline yield unaffected by environmental conditions.
  • Replicating the test across multiple locations or years to generalize the findings beyond a single environmental condition.
A well-crafted experimental design allows researchers to draw more accurate and reliable conclusions by reducing errors and biases.
Variables in Statistics
Variables in statistics are elements that researchers study, and their values can change. They can be classified into different types based on how they are used in an analysis.
In the corn yield scenario:
  • The independent variable is the type of corn variety, which is what we manipulate to observe changes.
  • The dependent variable is the yield, the outcome we measure.
  • Other factors like the environmental conditions (e.g., the year’s drought) can act either as confounders or moderators of the effect.
Understanding and correctly labeling variables can help to clearly define the scope of a study and focus the analysis on the right areas.
Statistical Analysis
Statistical analysis is the process of collecting, reviewing, and interpreting data in order to derive insights and make decisions. It allows researchers to summarize complex data and extract meaningful patterns.
In our example, comparing the yields of different corn varieties involves analyzing the data to understand if the difference observed is statistically significant or just due to random chance.
Techniques such as regression analysis could be used to account for the effects of the drought as a confounding variable, helping to focus solely on the effect of corn variety differences. Well-conducted statistical analysis aids in translating raw data into actionable insights and informed decision-making.

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