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# Variables, Sample, and Population

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1. A researcher is interested in the effects of humidity on the eating behavior rats. A group of 25 rats is housed in a controlled environment and the researcher measures the amount of food consumed by each rat with humidity set at 20% and again with the humidity set at 80%.
a. Identify the population
b. Identify the sample

2. Define the terms population, sample, parameter, and statistic. Explain the relationships among the terms

3. Statistical methods are classified into two major categories: descriptive and inferential. Describe the general purpose for the statistical methods in each category.

4. Define the concept of sampling error. Be sure that your definition includes the concepts of statistic and parameter.

16. Define and differentiate between a discrete variable and a continuous variable

17. A researcher studying the effects of environment on mood asks participation to sit alone in a waiting room for 15 minutes at the beginning of an experiment. Half of them are assigned to a room with dark blue walls, and the other half are assigned to a room with bright yellow walls. After 15 minutes in the waiting room, each participant is brought into the lab and given a mood-assessment questionnaire. The score on the mood questionnaire are then examined.
a. Identify the independent and dependent variables for this study
b. What scale of measurement is used for the independent variable?

18. For the following scores, find the value of each expression:
X= 5,2,1,4,
a. Sigma X , X=
b. Sigma X²
c. Sigma X)²
d. Sigma (X-1)
See attached file for full problem description.

https://brainmass.com/statistics/sampling/variables-sample-population-120515

#### Solution Summary

Answers questions on Population, sample, parameter, statistic, discrete variable and a continuous variable, independent and dependent variables, scale of measurement.

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