# 3.9 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.

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
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
how did you get the value of 2000N.What calculations are needed to arrive at it
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