STAT
STAT 222 Module 8 QA.pdf

# Enter the data into the corrregression applet produce

• Homework Help
• 73

This preview shows pages 15–17. Sign up to view the full content.

Enter the data into the Corr/Regression applet. Produce a scatterplot and comment on the association between the variables as revealed in the scatterplot. (Remember to comment on form, direction, strength, and unusual observations.) There is a fairly strong negative association between age and price of the cars. Not much unusual except perhaps the oldest and cheapest car. See scatterplot for Solution f. Report the value of the correlation coefficient. Does the value of the correlation coefficient support your answer in part (f)? Explain how you are deciding. The correlation of -0.820 backs up the answer to part (f) because it is close to -1. Describe how one might use everyday items (for example, coins, dice, cards, etc.) to conduct a tactile simulation-based test of the hypotheses. Be sure to clearly describe how the p-value will be computed from the simulation. Put the 90 ages on 90 index cards and the 90 prices on 90 other index cards. Shuffle the price index cards and randomly match them up with the 90 age cards. From this data set, compute the correlation coefficient. That simulated correlation coefficient will be one dot in the null distribution. Repeat this many, many times to create a null distribution. Find the proportion of simulated correlation coefficients that are -0.820 or below along with the simulated correlation coefficients that are 0.820 or above. This proportion will be the estimated p-value. Chapter 10.2 Exercise Question 08 Refer to the previous exercise about the association between the age and price of used Honda Civics. Consider conducting a test of significance to investigate whether the sample data provide

This preview has intentionally blurred sections. Sign up to view the full version.

strong evidence of an association between a car's price and age in the population of used Honda Civics. The data are in the file UsedHondaCivics . Enter the data into the Corr/Regression applet and conduct a simulation-based test of significance using the correlation coefficient as the statistic. Report the approximate p-value. The p-value is about 0. Interpret the p-value reported in part (a). If there is no association between age and price of used Honda Civics, the probability we would get a sample correlation coefficient at least as extreme as -0.820 is about 0. Summarize your conclusion (significance, causation, generalizability) from this simulation analysis. Also describe the reasoning process by which your conclusion follows from your simulation results. We have extremely strong evidence (small p-value) that there is an association between a car's price and its age in the population of all used Honda Civics advertised online. Because our sample correlation coefficient is negative, we can add that the association is negative in the population. Because this was an observational study, we are not drawing any causal conclusions.
This is the end of the preview. Sign up to access the rest of the document.
• Summer '18
• Null hypothesis, Statistical hypothesis testing, Correlation and dependence, Pearson product-moment correlation coefficient

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern