Sat practice Test #8 Answer Explanations

Choice C is correct. According to the graph, the number of figurines 
decreased between 1 and 2 months and between 3 and 4 months. 
Because the line segment between 3 and 4 months is steeper than the 
line segment between 1 and 2 months, it follows that the number of 
figurines decreased the fastest between 3 and 4 months.
Choice A is incorrect. Between 1 and 2 months, the number of 
figurines decreased. However, the number of figurines decreased 
faster during the interval between 3 and 4 months. Choices B and D 
are incorrect. The number of figurines during these intervals was 
increasing, not decreasing.
QUESTION 3
Choice A is correct. The fraction of the cars in the random sample 
that have a manufacturing defect is 3 
_ 
200 = 0.015. At this rate, out 
of 10,000 cars there would be 0.015 × 10,000 = 150 cars that have a 
manufacturing defect.
Choices B, C, and D are incorrect because the fractions of cars in
the population that have a defect, 200 
_
10,000 = 0.02 in choice B, 
250 
_
10,000 = 0.025 in choice C, and
300 
_
10,000 = 0.03 in choice D, are all 
different from the fraction of cars in the sample with a manufacturing 
defect, which is 0.015.
QUESTION 4
Choice C is correct. The given line of best fit can be used to predict 
the length when the width is known. The equation of the line of best 
fit is given as y = 1.67x + 21.1, where x is the width in millimeters and 
y is the predicted length in millimeters. If the width of the petal is 
19 millimeters, then x = 19 and y = 1.67(19) + 21.1 = 52.83.

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Choice A is incorrect and may result from incorrectly using x = 0 in the 
equation. Choice B is incorrect and may result from neglecting to add 
21.1 in the computation. Choice D is incorrect and may result from an 
arithmetic error.
QUESTION 5