# 12.12 Homework

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Linear Regression and Correlation: Homework is a part of Collaborative Statistics collection (col10522) by Barbara Illowsky and Susan Dean.

For each situation below, state the independent variable and the dependent variable.

• A study is done to determine if elderly drivers are involved in more motor vehicle fatalities than all other drivers. The number of fatalities per 100,000 drivers is compared to the age of drivers.
• A study is done to determine if the weekly grocery bill changes based on the number of family members.
• Insurance companies base life insurance premiums partially on the age of the applicant.
• Utility bills vary according to power consumption.
• A study is done to determine if a higher education reduces the crime rate in a population.
• Independent: Age; Dependent: Fatalities
• Independent: Power Consumption; Dependent: Utility
For any prediction questions, the answers are calculated using the least squares (best fit) line equation cited in the solution.

Recently, the annual number of driver deaths per 100,000 for the selected age groups was as follows (Source: http:// http://www.census.gov/compendia/statab/cats/transportation/motor_vehicle_accidents_and_fatalities.html ):

Age Number of Driver Deaths per 100,000
16-19 38
20-24 36
25-34 24
35-54 20
55-74 18
75+ 28

• For each age group, pick the midpoint of the interval for the x value. (For the 75+ group, use 80.)
• Using “ages” as the independent variable and “Number of driver deaths per 100,000” as the dependent variable, make a scatter plot of the data.
• Calculate the least squares (best–fit) line. Put the equation in the form of: $\stackrel{^}{y}=a+\text{bx}$
• Find the correlation coefficient. Is it significant?
• Pick two ages and find the estimated fatality rates.
• Use the two points in (e) to plot the least squares line on your graph from (b).
• Based on the above data, is there a linear relationship between age of a driver and driver fatality rate?
• What is the slope of the least squares (best-fit) line? Interpret the slope.

The average number of people in a family that received welfare for various years is given below. (Source: House Ways and Means Committee, Health and Human Services Department )

Year Welfare family size
1969 4.0
1973 3.6
1975 3.2
1979 3.0
1983 3.0
1988 3.0
1991 2.9

• Using “year” as the independent variable and “welfare family size” as the dependent variable, make a scatter plot of the data.
• Calculate the least squares line. Put the equation in the form of: $\stackrel{^}{y}=a+\text{bx}$
• Find the correlation coefficient. Is it significant?
• Pick two years between 1969 and 1991 and find the estimated welfare family sizes.
• Use the two points in (d) to plot the least squares line on your graph from (b).
• Based on the above data, is there a linear relationship between the year and the average number of people in a welfare family?
• Using the least squares line, estimate the welfare family sizes for 1960 and 1995. Does the least squares line give an accurate estimate for those years? Explain why or why not.
• Are there any outliers in the above data?
• What is the estimated average welfare family size for 1986? Does the least squares line give an accurate estimate for that year? Explain why or why not.
• What is the slope of the least squares (best-fit) line? Interpret the slope.
• $\stackrel{^}{y}=\text{88}\text{.}\text{7206}-0\text{.}\text{0432}x$
• -0.8533, Yes
• No
• No.
• 2.93, Yes
• slope = -0.0432. As the year increases by one, the welfare family size tends to decrease by 0.0432 people.

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are nano particles real
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Joseph
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no can't
Lohitha
where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
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da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
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Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
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Alexandre
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Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
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Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
how did you get the value of 2000N.What calculations are needed to arrive at it
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1 It is estimated that 30% of all drivers have some kind of medical aid in South Africa. What is the probability that in a sample of 10 drivers: 3.1.1 Exactly 4 will have a medical aid. (8) 3.1.2 At least 2 will have a medical aid. (8) 3.1.3 More than 9 will have a medical aid.