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Chapter 12 Homework
Question 1: What are the dependent and independent variables?
Dependent variable: fee amount
Independent variable: time
Question 2: Find the equation that expresses the total fee in terms of the number
of hours the equipment is rented
Y = 25 + 12.5x
Question 3: Graph the equation
Question 7: Which of the following equations are linear?
The form of linear equation is; y = a + bx
Y = 6x + 8; y+ 7 = 3x; 4y = 8
Question 8: Does the graph show a linear equation? Why or why not?
It does not show a linear equation since there is no straight-line showing relationship.
Question 10: What are the independent and dependent variables?
Independent variable; time (hours)
Dependent variables; labor fee
Question 12: What are the independent and dependent variables?
Independent variable; erosion
0
20000
40000
60000
80000
100000
Pre- 1981
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
Totala deathsa anda cases
Year
Flua casea againsta fluea deaths
# flu cases diagnosed # flu deaths
2
Dependent variable; pounds (amount of soil lost)
Question 13: How many pounds of soil does the shoreline lose in a year?
12,000 pounds
Question 15: What are the slope and y-intercept? Interpret their meaning
y = 15 – 1.5x
(a form of the linear equation; y = a + bx; where a is y-intercept and b is slope)
slope;-(1.5); stock losses value at the rate of $1.5 per hour
y-intercept; 15; the price stock before trading $15
Question 17: Does the scatter plot appear linear? Strong or weak? Positive or
negative?
The data is linear with a strong, positive correlation.
Question 18: Does the scatter plot appear linear? Strong or weak? Positive or
negative?
The data is linear with a strong negative correlation
Question 19: Does the scatter plot appear linear? Strong or weak? Positive or
negative?
The data appears to have no correlation
Question 20: Draw a scatter plot of the data
Question 21: Use regression to find the equation for the line of the best fit
y = 1.9875x + 2.2336
Question 22: Draw the line of best fit on the scatter plot
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2
4
6
8
10
12
14
0 1 2 3 4 5 6
Y-a variablea
X-a variable
Scatter-a plot
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Question 25: What does an r-value of zero mean?
It means there exists no correlation between the variables in question
Question 30: If the level of significance is 0.05 and the p-value is 0.04, what
conclusion can you draw?
The conclusion will be the variable are statistically significant and conclude b rejecting
the null hypothesis.
Question 33: How many acres will be left to mow after 20 hours of work
y = 1350 – 1.2x
y = 1350 – (1.2* 20)
y = 1326 acres
Question 34: How many acres will be left to mow after 100 hours of work
y = 1350 – 1.2x
y = 1350 – (1.2* 100)
y = 1350- 120
y = 1230 acres
Question 38: Find the correlation coefficient
r = 0.954087
0
2
4
6
8
10
12
14
0 1 2 3 4 5 6
Y-a variablea
X-a variable
Scatter-a plot
