Question

6. How would driving speed relate to fuel efficiency? A study on driving speed (miles per hour) and fuel efficiency (miles per gallon) resulted in the following sample data for sedans:

Driving Speed 30 50 40 55 30 25 60 25 50 55

Fuel Efficiency 28 25 25 23 30 32 21 35 26 25

a. Construct a scatter plot with driving speed on the horizontal axis and fuel efficiency on the vertical axis

b. Calculate the mean, median, variance, and standard deviation for each variable.

c. Judging from the scatter plot, comment on the relationship between the two variables.

d. Calculate the correlation between the two variables. Are they strongly related?

Answer #1

Using excel to show the working.

a)

b)

b

C) By observing the scatter plot we see that driving speed and fuel effeciency os negatively correlated. When one goes down the other increases.

d) Using the correl funtion , I found out the correlation of both the variable in excel. It came up to be -.910369. This means they have a strong correlation which is negatively.

A number which is inclined towards -1 shows that they are negatively correlated.

A department of transportation’s study on driving speed and
miles per gallon for midsize automobiles resulted in the following
data:
Speed (Miles per Hour)Miles per Gallon: 30 51 39 55 30
24 61 24 50 56
Miles per Gallon: 29 25 25 23 31 33 20 35 26
24
Compute the sample correlation coefficient (to 2 decimals and
enter negative value as negative number).
What can you conclude, based on your computation of the sample
correlation coefficient?

Fuel efficiency, measured in miles per gallon, for many vehicles
follows a symmetric and bell shaped distribution. Suppose the city
driving fuel efficiency of a 2009 Honda Odyssey has an average of
17mpg with a standard deviation of 2.2 mpg. What percentage of 2009
Honda Odysseys have a fuel efficiency between 12.6mpg and
19.2mpg?
Answer:???

A family has two cars. The first car has a fuel efficiency of 20
miles per gallon of gas and the second has a fuel efficiency of 30
miles per gallon of gas. During one particular week, the two cars
went a combined total of 1050 miles, for a total gas consumption of
45 gallons. How many gallons were consumed by each of the two cars
that week?

The fuel efficiency, in miles per gallon, of 12 small utility
trucks was measured are recorded as follows:
.........
.........
.........
.........
...... ...
..... ....
.........
.........
..... ....
.........
.........
.........
21
26
23
26
15
24
23
32
23
21
25
22
.
For this sample, calculate the following
measures:
.
Sum of All Data Values
Sum of All Deviations
Sum of All Squared
Deviations Round to the nearest
hundredth

The data in the table present the speed of an automobile (miles
per hour) and its corresponding gasmileage (miles per gallon).
Speed 30 40 50 60 70
Gas-Mileage 24 28 30 28 24
1. Which is the explanatory variable, and which is the
response?
2. Make a scatterplot of Mileage vs Speed. (Choose the
appropriate scales, and use a ruler for the plot).
3. Is the association between the two variables positive or
negative? Explain.
4. Compute the correlation r...

The airlines industry measures fuel efficiency by calculating
how many miles one seat can travel, whether occupied or not, on one
gallon of jet fuel. The following data show the fuel economy, in
miles per seat for 19 randomly selected flights on Delta and
United. Assume the two population variance for fuel efficiency for
the two airline are equal.
Delta
United
65.80
82.10
81.40
58.80
58.90
60.00
73.60
57.90
72.90
62.80
53.20
45.20
49.80
54.30
68.30
68.40
61.40
52.00
73.10...

- Following are the fuel efficiency, in miles per gallon, for a
sample of convertibles. Calculate the sample variance. 25, 23 , 25,
20, 21 Write only a number as your answer.
Round to one decimal place (for example: 8.3).
- Following are playback time, in hours, for a sample of MP3
players, Calculate the sample standard deviation.
23,35,28,18,25,21,37,28 Write only a number as your answer. Round
to two decimal place (for example: 8.32).
- Following are closing prices of...

QUESTION 15
The speed x (in mph) of a car and the related average miles per
gallon y for each speed x are given. Find the quadratic regression
model that best fits the following data: (30, 18), (40, 23), (50,
28), (60, 29), (70, 25)
Round all calculations to two decimal places.
none of these
Y(x) = -.02x2 - 2.80x + 22.00
Y(x) = -.02x2 + 2.00x - 22.00
Y(x) = -.02x 2 + 1.77x - 21.54

Brawdy Plastics, Inc., produces plastic seat belt retainers for
General Motors at the Brawdy Plastics plant in Buffalo, New York.
After final assembly and painting, the parts are placed on a
conveyor belt that moves the parts past a final inspection station.
How fast the parts move past the final inspection station depends
upon the line speed of the conveyor belt (feet per minute).
Although faster line speeds are desirable, management is concerned
that increasing the line speed too much...

Brawdy Plastics, Inc., produces plastic seat belt retainers for
General Motors at the Brawdy Plastics plant in Buffalo, New York.
After final assembly and painting, the parts are placed on a
conveyor belt that moves the parts past a final inspection station.
How fast the parts move past the final inspection station depends
upon the line speed of the conveyor belt (feet per minute).
Although faster line speeds are desirable, management is concerned
that increasing the line speed too much...

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