Question
Problem 1 : The table below contains the value of the house and the amount of rental income in a year that the house brings
Problem 1:
The table below contains the value of the house and the amount of rental income in a year that the house brings in when rented. Answer all parts (a) through (e).
(a) Create a scatter plot of the data. What kind of association does the scatter plot suggest (e.g., positive linear, etc.)
(b) Using technology (e.g., Excel's Regression Tool or the TI 84 calculator), determine the following:
(i) Find the linear correlation coefficient "r". Provide an interpretation.
(ii) Find the coefficient of determination "R2". Provide an interpretation.
(iii) Find the equation of the least squares regression line between the value of the house and the amount of rental income in a year that the house brings in when rented.
(c) Using the equation from part (b)(iii), find the following:
(i) Estimate the rental income for a house worth $230,000;
(ii) Estimate the rental income for a house worth $400,000.
(d) Which rental income that you calculated in part(c) is a more accurate estimate of the true rental income? Why?
(e) Test at the 5% level for a positive correlation between house value and rental amount. Specifically, do the following:
(i) Set up the appropriate null and alternative hypotheses.
(ii) Verify that the assumptions necessary to apply the test are satisfied.
(iii) What is the test statistic and what is the p-value?
(iv) State your conclusion.
Table: Data of House Value versus Rental
Value | Rental | Value | Rental | Value | Rental | Value | Rental |
81000 | 6656 | 77000 | 4576 | 75000 | 7280 | 67500 | 6864 |
95000 | 7904 | 94000 | 8736 | 90000 | 6240 | 85000 | 7072 |
121000 | 12064 | 115000 | 7904 | 110000 | 7072 | 104000 | 7904 |
135000 | 8320 | 130000 | 9776 | 126000 | 6240 | 125000 | 7904 |
145000 | 8320 | 140000 | 9568 | 140000 | 9152 | 135000 | 7488 |
165000 | 13312 | 165000 | 8528 | 155000 | 7488 | 148000 | 8320 |
178000 | 11856 | 174000 | 10400 | 170000 | 9568 | 170000 | 12688 |
200000 | 12272 | 200000 | 10608 | 194000 | 11232 | 190000 | 8320 |
214000 | 8528 | 208000 | 10400 | 200000 | 10400 | 200000 | 8320 |
240000 | 10192 | 240000 | 12064 | 240000 | 11648 | 225000 | 12480 |
289000 | 11648 | 270000 | 12896 | 262000 | 10192 | 244500 | 11232 |
325000 | 12480 | 310000 | 12480 | 303000 | 12272 | 300000 | 12480 |
Problem 2:The World Bank collected data on the percentage of GDP that a country spends on health expenditures and also the percentage of women receiving prenatal care. The data for the countries where this information are available for the year 2011 is in the table below. Answer all parts (a) through (e).
(a) Create a scatter plot of the data. What kind of association does the scatter plot suggest (e.g., positive linear, etc.)
(b) Using technology (e.g., Excel's Regression Tool or the TI 84 calculator), determine the following:
(i) Find the linear correlation coefficient "r". Provide an interpretation.
(ii) Find the coefficient of determination "R2". Provide an interpretation.
(iii) Find the equation of the least squares regression line between percentage spent on health expenditures and the percentage of women receiving prenatal care.
(c) Using the equation from part (b)(iii), find the following:
(i) Estimate the percent of women receiving prenatal care for a country that spends 5.0% of GDP on health expenditures;
(ii) Estimate the percent of women receiving prenatal care for a country that spends 12.0% of GDP on health expenditures.
(d) Which prenatal care percentage that you calculated in part (c) do you think is closer to the true percentage? Why?
(e) Test at the 5% level for a correlation between percentage spent on health expenditures and the percentage of women receiving prenatal care. Specifically, do the following:
(i) Set up the appropriate null and alternative hypotheses.
(ii) Verify that the assumptions necessary to apply the test are satisfied.
(iii) What is the test statistic and what is the p-value?
(iv) State your conclusion.
Table: Data of Health Expenditure versus Prenatal Care
Health Expenditure (% of GDP) | Prenatal Care (%) |
9.6 | 47.9 |
3.7 | 54.6 |
5.2 | 93.7 |
5.2 | 84.7 |
10.0 | 100.0 |
4.7 | 42.5 |
4.8 | 96.4 |
6.0 | 77.1 |
5.4 | 58.3 |
4.8 | 95.4 |
4.1 | 78.0 |
6.0 | 93.3 |
9.5 | 93.3 |
6.8 | 93.7 |
6.1 | 89.8 |
Problem 3:
Researchers watched groups of dolphins off the coast of Ireland in 1998 to determine what activities (travel, feed, social) the dolphins partake in at certain times of the day. The numbers in the table below represent the number of groups of dolphins that were partaking in an activity at certain times of days.
Set up and run a test of hypothesis to determine ifthere is enough evidence to show that the activity and the time period are independent for dolphins. Use a level of significance of 1%. Specifically, do the following:
(i) Write down the null and alternative hypotheses.
(ii)Verify that the assumptions necessary to apply the test are satisfied.
(iii) What is the test statistic and what is the p-value?
(iv) State your conclusion
Table: Dolphin Activity
Activity | Period | Row Total | |||
Morning | Noon | Afternoon | Evening | ||
Travel | 6 | 6 | 14 | 13 | 39 |
Feed | 28 | 4 | 0 | 56 | 88 |
Social | 38 | 5 | 9 | 10 | 62 |
Column Total | 72 | 15 | 23 | 79 | 189 |
Problem 4.
A person's educational attainment and age group were collected by the U.S. Census Bureau in 1984 to see if age group and educational attainment are related. The counts in thousands are in the table below.
Set up and run a test of hypothesis to determine ifthere is enough evidence to show that educational attainment and age are independent. Use a level of significance of 5%. Specifically, do the following:
(i) Write down the null and alternative hypotheses.
(ii)Verify that the assumptions necessary to apply the test are satisfied.
(iii) What is the test statistic and what is the p-value?
(iv) State your conclusion
Table: Educational Attainment and Age Group
Education | Age Group | Row Total | ||||
25-34 | 35-44 | 45-54 | 55-64 | >64 | ||
Did not complete HS | 5416 | 5030 | 5777 | 7606 | 13746 | 37575 |
Competed HS | 16431 | 1855 | 9435 | 8795 | 7558 | 44074 |
College 1-3 years | 8555 | 5576 | 3124 | 2524 | 2503 | 22282 |
College 4 or more years | 9771 | 7596 | 3904 | 3109 | 2483 | 26863 |
Column Total | 40173 | 20057 | 22240 | 22034 | 26290 | 130794 |
Problem 5.
In Africa in 2011, the number of deaths of a female from cardiovascular disease for different age groups are in the table below. Also, the proportion of deaths of females from all causes for the same age groups are in the table.
Set up and run a test of hypothesis to determine ifdeaths from cardiovascular disease are in the same proportion as all deaths for the different age groups. Use a level of significance of 5%. Specifically, do the following:
(i) Write down the null and alternative hypotheses.
(ii)Verify that the assumptions necessary to apply the test are satisfied.
(iii) What is the test statistic and what is the p-value?
(iv) State your conclusion
Table: Deaths of Females for Different Age Groups
Age | Cardiovascular Frequency | All Cause Proportion |
"5 - 14" | 8 | 0.10 |
"15 - 29" | 16 | 0.12 |
"30 - 49" | 56 | 0.26 |
"50 - 69" | 433 | 0.52 |
TOTAL | 513 |
Problem 6.
A project conducted by the Federal Office of Road Safety asked people many questions about their cars. One question asked was: "What is the primary reason that a person chooses a particular car?" The data is contained in the table below.
Table: Reason for Choosing a Car
SAFETY | 84 |
RELIABILITY | 62 |
COST | 46 |
PERFORMANCE | 34 |
COMFORT | 47 |
LOOKS | 27 |
TOTAL | 300 |
Set up and run a test of hypothesis to determine ifthe frequencies observed substantiate the claim that the reasons for choosing a car are equally likely. Use a level of significance of 5%. Specifically, do the following:
(i) Write down the null and alternative hypotheses.
(ii)Verify that the assumptions necessary to apply the test are satisfied.
(iii) What is the test statistic and what is the p-value?
(iv) State your conclusion
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