Juan wishes to compare the percentages of time he spends on different tasks during the workday. Which of the following representations is the most appropriate choice for displaying the data?
- A. Line plot
- B. Bar graph
- C. Line graph
- D. Pie chart
Correct Answer: D
Rationale: A pie chart is the most appropriate choice for displaying the percentages of time spent on different tasks during the workday because it visually represents parts of a whole. In this case, each task's percentage represents a part of the entire workday, making a pie chart an ideal way to compare these percentages. Line plots, bar graphs, and line graphs are not suitable for showing percentages of a whole; they are more commonly used for tracking trends, comparing values, or showing relationships between variables but do not efficiently represent parts of a whole like a pie chart does.
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Express the solution to the following problem in decimal form:
- A. 0.042
- B. 84%
- C. 0.84
- D. 0.42
Correct Answer: C
Rationale: The correct answer is C: 0.84. To convert a percentage to a decimal, you divide the percentage value by 100. In this case, 84% divided by 100 equals 0.84. Choice A, 0.042, is not the correct conversion of 84%. Choice B, 84%, is already in percentage form and needs to be converted to a decimal. Choice D, 0.42, is not the correct conversion of 84% either. Therefore, the correct decimal form of 84% is 0.84.
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.
In Jim's school, there are 3 girls for every 2 boys. There are 650 students in total. Using this information, how many students are girls?
- A. 260
- B. 130
- C. 65
- D. 390
Correct Answer: A
Rationale: To find the number of girls in Jim's school, we first establish the ratio of girls to boys as 3:2. This ratio implies that out of every 5 students (3 girls + 2 boys), 3 are girls and 2 are boys. Since there are a total of 650 students, we can divide them into 5 equal parts based on the ratio. Each part represents 650 divided by 5, which is 130. Therefore, there are 3 parts of girls in the school, totaling 3 multiplied by 130, which equals 390. Hence, there are 390 girls in Jim's school. Choice A, 260, is incorrect as it does not consider the correct ratio and calculation. Choice B, 130, is incorrect as it only represents one part of the total students, not the number of girls. Choice C, 65, is incorrect as it ignores the total number of students and the ratio provided.
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.
On a floor plan drawn at a scale of 1:100, the area of a rectangular room is 50 cm². What is the actual area of the room?
- A. 500 m²
- B. 50 m²
- C. 5000 cm²
- D. 500 cm²
Correct Answer: D
Rationale: The scale of 1:100 means that 1 cm² on the floor plan represents 100 cm² in real life. To find the actual area of the room, you need to multiply the area on the floor plan by the square of the scale factor. Since the scale is 1:100, the scale factor is 100. Therefore, 50 cm² on the floor plan represents 50 * 100 = 5000 cm² in real life. Choice A (500 m²) is incorrect as it converts the area from cm² to m² without considering the scale factor. Choice B (50 m²) is incorrect as it does not account for the scale factor. Choice C (5000 cm²) is incorrect as it gives the area on the floor plan, not the actual area.
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