What is the overall median of Dwayne's current scores: 78, 92, 83, 97?
- A. 19
- B. 85
- C. 83
- D. 87.5
Correct Answer: B
Rationale: To find the median of a set of numbers, first arrange the scores in ascending order: 78, 83, 92, 97. Since there is an even number of scores, we find the median by taking the average of the two middle values. In this case, the middle values are 83 and 92. Calculating (83 + 92) / 2 = 85, we determine that the overall median of Dwayne's scores is 85. Choice A (19) is incorrect as it does not correspond to any value in the given set of scores. Choice C (83) is the median of the original set but not the overall median once arranged. Choice D (87.5) is the average of all scores but not the median.
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A student gets an 85% on a test with 20 questions. How many answers did the student solve correctly?
- A. 15
- B. 16
- C. 17
- D. 18
Correct Answer: C
Rationale: To determine the number of questions the student solved correctly, we need to calculate 85% of the total number of questions. This can be done by multiplying the total number of questions by 85%, which is 20 questions x 85% = 20 x 0.85 = 17 questions. Therefore, the student solved 17 questions correctly. Choice A, 15, is incorrect as it does not reflect the correct percentage of questions solved. Choice B, 16, and Choice D, 18, are also incorrect as they do not match the calculation based on the given percentage.
Kimberley earns $10 an hour babysitting, and after 10 p.m., she earns $12 an hour, with the amount paid being rounded to the nearest hour accordingly. On her last job, she worked from 5:30 p.m. to 11 p.m. In total, how much did Kimberley earn on her last job?
- A. $45
- B. $57
- C. $62
- D. $42
Correct Answer: C
Rationale: Kimberley worked from 5:30 p.m. to 11 p.m., which is a total of 5.5 hours before 10 p.m. (from 5:30 p.m. to 10 p.m.) and 1 hour after 10 p.m. The earnings she made before 10 p.m. at $10 an hour was 5.5 hours * $10 = $55. Her earnings after 10 p.m. for the rounded hour were 1 hour * $12 = $12. Therefore, her total earnings for the last job were $55 + $12 = $67. Since the amount is rounded to the nearest hour, the closest rounded amount is $62. Therefore, Kimberley earned $62 on her last job. Choice A is incorrect as it does not consider the additional earnings after 10 p.m. Choices B and D are incorrect as they do not factor in the hourly rates and the total hours worked accurately.
A quantity increases from 40 to 60. Express this increase as a percentage.
- A. 26%
- B. 50%
- C. 35%
- D. 12%
Correct Answer: B
Rationale: To calculate the percentage increase, use the formula:
Percentage Increase = ((New Value - Original Value) / Original Value) x 100
Substitute the values:
((60 - 40) / 40) x 100 = (20 / 40) x 100 = 0.5 x 100 = 50%
Therefore, the correct answer is 50%.
Choice A (26%) is incorrect as the percentage increase is not 26%. Choice C (35%) is incorrect as the percentage increase is not 35%. Choice D (12%) is incorrect as the percentage increase is not 12%.
When the sampling distribution of means is plotted, which of the following is true?
- A. The distribution is approximately normal.
- B. The distribution is positively skewed.
- C. The distribution is negatively skewed.
- D. There is no predictable shape to the distribution.
Correct Answer: A
Rationale: When the sampling distribution of means is plotted, the distribution tends to be approximately normal, especially as the sample size increases. This phenomenon is described by the Central Limit Theorem, which states that the sampling distribution of the sample mean will be normally distributed regardless of the shape of the original population distribution as long as the sample size is sufficiently large. Choices B and C are incorrect because sampling distributions of means are not skewed. Choice D is incorrect because there is a predictable shape to the distribution, which is approximately normal.
Alan currently weighs 200 pounds, but he wants to lose weight to get down to 175 pounds. What is the difference in kilograms? (1 pound is approximately equal to 0.45 kilograms.)
- A. 9 kg
- B. 11.25 kg
- C. 78.75 kg
- D. 90 kg
Correct Answer: B
Rationale: The difference between Alan's current weight of 200 pounds and his goal weight of 175 pounds is 25 pounds (200 pounds - 175 pounds). To convert pounds to kilograms, you multiply the number of pounds by 0.45 (not divide by 2.2). Thus, 25 pounds is approximately 11.25 kilograms (25 pounds x 0.45). Therefore, the difference in kilograms is 11.25 kg. Choice A is incorrect because it miscalculates the conversion. Choices C and D are significantly higher values and do not reflect the correct conversion from pounds to kilograms.
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