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Unformatted text preview: Math 2311 Written Homework 6 (Sections 5.1 — 5.3) Name: KEY PeopleSoft ID: Instructions: 0 Homework will NOT be accepted through email or in person. Homework must be submittcd through
CourseWare BEFORE the deadline. 0 Print out this ﬁle and complete the problems. 0 Use blue or black ink or a dark pencil. 0 Write your solutions in the space provided. You must show all work for full credit. 0 Submit this assignment at http://www.casa.uh.edu under "Assignments" and choose th6. 1. Section 5.1, Problem 4 1 pt Weight is an explanatory variable and clothing size is the response variable 2. Section 5.1, Problem 8 1 pt Positive correlation 5.0 5.5 6.0 6.5 ?.0 ?.5 4.5 2 pts [Grade parts a) and b) only for 1 pt each. Parts c) and d) 3. Section 5.1,Problcm 10 _ _
are subjective] Age{months) Vs. Weight > a=(‘l :12)
> w=c(4.3,5.‘l,5.7,6.3,6.8,7.‘l ,7.2,7.2,7.2,7.2,7.5,7.8)
O > plot(a,w, main = "Age(months) Vs. Weight“)
0 b) Positive
0 c) No
— d) no, due to nonlinearity or I would not predict
° this future value because of extrapolation 4. Section 5.2, Problem} 2 pts (1 pt each) > x=c(75,8‘l,57,79,68,93,96,84,41,89) a) > y=c(2,3,‘l,2,’l,4.4.3.1.3)
> p0t()(,y)
> cor x, g 0 O ( y) in. ('0 g 0 0 O to m b) 0.8945 g 0 0 Ln_ 2 o o 0 4O 50 50 70 80 90 5. Section 5.3, Problem 14 3 pts (1 pt each) > X:C(2 5 Q 6)
> y=0(9.’.11.2) > cor(x,y) a) O.940, strong negative relationship > (com yore)” 00 b) 0.8843; 88.43% of the variation of y is explained by the LSRL > WOW)
_ Call:
— 9.239  1.632*
C) y X lm(formula = y  x)
Coefficients:
(Intercept) x
9.239 1 .632 6. Section 5.3, Problem 16 1 pt (Completion grade) For every degree that the temperature exceeds 50 degrees, there is ~3.4’l more chirps per
minute. [’90 7. Section 5.3, Problem 18 104 108 108 102 5 pts (1 pt each) NOTE: Some students will have years as 1925, 1935,
etc. Do not count off for this but make a remark that each x should
represent 10 years after 1925. Ex below: 0:1925, 10:1935, etc. Record Vs Year YF=C(0.10.20.30.40.50.60.70)
> rec=c(1119,109.7,106.6,105.7,104.3,104
1,101.73,101.73) > plot(yr, rec, main = "Record Vs. Year")
> m(rec~yr) Call:
m(formula = rec  yr) 0 Coefficients:
o (I ntercept) yr
110.7175 0.1428 cor(yr,rec)"2*100 yr b) LSRL is y = yl NT  0.143*x (yintercept can be whatever because it depends or
the x axis the students chose) 0) The time for the world record has been decreasing by ~0.143 units every 1
year d) 0.969; There is strong negative correlation between the explanatory and
response variables e) 0.9380; 93.80% of variation in the record times is explained by the LSRL. This
is a fairly strong relationship with which we can make predictions with ...
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 Fall '08
 HAFEEZ

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