STAT 200 Week 1 Homework Problems Solutions, University of Maryland University College (UMUC)

STAT 200 Week 1 Homework Problems 1.1.4 To estimate the percentage of households in Connecticut which use fuel oil as a heating source, a researcher collects information from 1000 Connecticut households about what fuel is their heating source. State the individual, variable, population, sample, parameter, and statistic Individual - Households in Connecticut. Variable - Percentage of households in Connecticut which use fuel oil as a heating source. Population - All responses from the samples. Sample - 1000 Connecticut households. Parameter - Percentage of household which use fuel oil as heating source. Statistic - Percentage of households which use fuel oil as heating source and other methods of heating sources taken from the samples. 1.1.8 The World Health Organization wishes to estimate the mean density of people per square kilometer, they collect data on 56 countries. State the individual, variable, population, sample, parameter, and statistic Individual - One country out of the 56 samples. Variable - The mean density of people per square kilometer from all 56 samples. Population - All the countries in the world. Sample - 56 countries. Parameter - The mean density of people per square kilometer from all the countries in the world. Statistic - The mean density of people per square kilometer. 1.2.4 You wish to determine the GPA of students at your school. Describe what process you would go through to collect a sample if you use a stratified sample. 1. Get a list of all the students in school. 2. Separate students by their major. 3. Conduct a simple random sample from each group of each major. 1.3.4 To evaluate whether a new fertilizer improves plant growth more than the old fertilizer, the fertilizer developer gives some plants the new fertilizer and others the old fertilizer. Is this an observation or an experiment? Why? it is an experiment because the developer is giving the new fertilizer to some plants and the old fertilizer to other in order to determine which fertilizer improve plant growth. 1.3.10 A mathematics instructor wants to see if a computer homework system improves the scores of the students in the class. The instructor teaches two different sections of the same