Week 1 Homework Problems PDF

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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: Heating source used in Connecticut households Population: All households in Connecticut Sample: 1000 Connecticut households Parameter: % of Connecticut households using fuel oil as a heating source Statistic: % in sample of 1000 Connecticut households using fuel oil as a heating source

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: People per square kilometer in the world Variable: Mean density per square kilometer Population: All people in the world Sample: Data from 56 countries Parameter: Mean density of people per square kilometer in the world Statistic: Mean density of people per square kilometer in the 56 countries

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. 

In order to collect a stratified sample, first you would determine the population. Then you would select a subgroup that you wish to stratify such as students by grade, by age, by gender, etc. Next, you would collect the data of GPA’s in that subgroup. Finally, you would calculate and get the data for the stratified sample.

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?

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This is an experiment because the variable was changed by the developer. The variable before was the old fertilizer and now the new fertilizer is being used as a variable as well.

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 course. One section utilizes the computer homework system and the other section completes homework with paper and pencil. Are the two samples matched pairs or not? Why or why not? 

No, the two samples are not matched pairs because the different students are used in each sample.

1.3.16 To determine if a new medication reduces headache pain, some patients are given the new medication and others are given a placebo. Neither the researchers nor the patients know who is taking the real medication and who is taking the placebo. Is this a blind experiment, double blind experiment, or neither? Why? 

It is a double blind experiment because neither the researchers or the patients know who is taking the real medication or the placebo.

1.4.2 Suppose a car dealership offers a low interest rate and a longer payoff period to customers or a high interest rate and a shorter payoff period to customers, and most customers choose the low interest rate and longer payoff period, does that mean that most customers want a lower interest rate? Explain. 

No, not necessarily. There are other factors that could be involved in the decision for what type loan they choose such as total price of the car, the down payment amount and the monthly payment amounts.

1.4.8 Suppose a telephone poll is conducted by contacting U.S. citizens via landlines about their view of gay marriage. Suppose over 50% of those called do not support gay marriage. Does that mean that you can say over 50% of all people in the U.S. do not support gay marriage? Explain 

No, that does not mean that over 50% of people in the U.S. do not support gay marriage. The people that were called and participated in the telephonic surveys were not a representative sample of the whole population because it only represents people who participated that have a landline and excludes those that have a cell phone only or no phone at all.

1.4.14 An employee survey says, “Employees at this institution are very satisfied with working here. Please rate your satisfaction with the institution.” Discuss how this question could create bias. 

The question could create bias- it leads people into answering a certain way because they claim most other employees at that company feel that way already. In order to

eliminate bias, the survey should simply state, “Please rate your satisfaction with the institution.” 2.1.4 In Connecticut households use gas, fuel oil, or electricity as a heating source. Table #2.1.7 shows the percentage of households that use one of these as their principle heating sources ("Electricity usage," 2013), ("Fuel oil usage," 2013), ("Gas usage," 2013). Create a bar chart and pie chart of this data. State any findings you see from the graphs. Table #2.1.7: Data of Household Heating Sources Heating Source Electricity Fuel Oil Gas Other

Percentage 15.3% 46.3% 35.6% 2.8%

Heating Sources in Connecticut Households 15.30%

Based off my observations 35.60% I have made from analyzing the data in the 46.30% bar and pie charts, I have concluded Electricity Fuel Oil Gas Other that households use fuel oil almost as much as households use all other heating sources combined. According to the charts, fuel oil and gas companies are the dominant providers in the heating source market. 2.80%

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