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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.
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What is the sixth number in the sequence 5, 6, 7, 8, 9?
- A. 8
- B. 10
- C. 11
- D. 12
Correct Answer: C
Rationale: In the given sequence 5, 6, 7, 8, 9, the sixth number would come after 9, not after the fifth number in the sequence. To find the sixth number, we need to continue the pattern after 9. The next number after 9 would be 10, making it the sixth number in the sequence. Therefore, the correct answer is not listed among the choices provided. Choice A, 8, is the fifth number in the sequence. Choice B, 10, is the number right after the sixth number. Choice D, 12, is not in the sequence at all, making it incorrect. Thus, the correct answer is 11.
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.
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 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.
Solve the following: 4 x 7 + (25 - 21)²
- A. 512
- B. 36
- C. 44
- D. 22
Correct Answer: B
Rationale: First, solve the expression inside the parentheses:
25
−
21
=
4
25−21=4
Then, square the result from the parentheses:
4
2
=
16
4
2
=16
Perform the multiplication:
4
7
=
28
47=28
Finally, add the results:
28
+
16
=
44
28+16=44