The standard deviation of n numbers $$x_{1}$$, $$x_{2}$$, $$x_{3}$$,......, $$x_{n}$$, with mean x is equal to $$\sqrt{\frac{s}{n}}$$, where S is the sum of the squared differences, $$(x_{i}- x)^{2}$$ for 1 ≤ i ≤ n.
List S: 3, 4, 7, 9, 10, 15
For which of the following lists is the standard deviation of the numbers in the list equal to 4 times the standard deivation of the numbers in list S?
Indicate all such lists.
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A certain list contains exactly five numbers. The median of the numbers in the list is 7, the mode (most frequently occurring number) of the numbers in the list is 4, and the average (arithmetic mean) of the greatest and second greatest numbers in the list is 20. What is the average of the numbers in this list?
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A survey of 300 travelers was taken at an airport. Of these travelers 90 percent were traveling on Airline A. Of those who were traveling on Airline A, 30 percent had first-class seats. Which of the following statements must be true about the 300 travelers?
Indicate all such statements.
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The standard deviation of the numbers in list K is a number between 12 and 15 inclusive. If a new list is formed by multiplying each number in list K by 3 which of the following values could be the standard deviation of the numbers in the new list?
Indicate all such values.
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In the rectangular coordinate system, the vertices R, S, and T of triangle RST have coordinates (3, 1), (3, 7), and (k, 4), respectively. If k > 3 which of the following must be true?
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A gardener plans to cover a rectangular plot of land with pine bark mulch to a depth of 4 inches.The plot measures 8 feet by 12 feet, and the gardener will buy mulch packed in bags. If each bag contains 3.5 cubic feet of mulch and costs $6,what is the cost of the least number of bags that the gardener will need to cover the plot? (Note: 1 foot=12 inches.)
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