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Homework Set #3
NAME:______________Rebecca Anderson_____ CM:______408_______
MA 223, Engineering Statistics
Spring 2008; 15 points possible
Due date:
Friday
, March 28
at the
BEGINNING of class (early submissions are acceptable)
.
You may work together on thinking through these problems, but what you turn in must be your own individual
write up and work.
Please show as much work as possible.
It’s much easier to give partial credit when the
work is all available.
•
Please clearly label your graphs
– including axes …
•
Please attach your Minitab work at the end of the homework set
.
You may cut and paste your
Minitab work into a word or notepad document.
_________________________________________________________________________________________
1.
TRUTH:
The National Weather Service Forecast Office puts out its own Cricket Chip Converter: You
enter the number of times a cricket chirps in 15 seconds, and the converter gives you the temperature estimated
in 4 different units, including degrees Fahrenheit and Celsius.
http://www.srh.noaa.gov/elp/wxcalc/cricketconvert.shtml
Here is some sample data for the number of cricket chirps in 15 seconds and accompanying temperatures in
degrees Fahrenheit:
Make a scatterplot of this data.
[Graph > Scatterplot]
Num Chirps in 15 sec
18
20
21
23
27
30
34
39
Temp (F)
57
60
64
65
68
71
74
77
(a) [+0.5] What is the predictor variable?
The # of chirps in 15 seconds
(b) [+0.5] What is the response variable?
Temperature
(c) [+0.5] Byhand, in Maple, or in Minitab, calculate the sample sample correlation coefficient
r
.
[
In Minitab:
Stat > Basic Statistics > Correlation]
.977
(d) [+0.5] The correlation coefficient
r
states the strength of the ___linear___________ relationship between
the predictor and response variables.
(e) [+1] In Minitab, the commands
Stat > Regression > Regression
gave the following output.
What is the
least squares regression line?
Write it in below in terms of
y
and
x
.
Round your slope and intercept to 3
decimal places.
Regression Analysis: Temp (F) versus Num Chirps in 15 sec
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View Full Document The regression equation is
Temp (F) = 43.0 + 0.906 Num Chirps in 15 sec
Predictor
Coef
SE Coef
T
P
Constant
42.997
2.186
19.67
0.000
Num Chirps in 15 sec
0.90576
0.07983
11.35
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This note was uploaded on 04/24/2008 for the course MA 223 taught by Professor Devasher during the Spring '08 term at RoseHulman.
 Spring '08
 DeVasher
 Statistics

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