Correct Answer: C

Rationale: The correct answer is C. Group B is negatively skewed, indicating more high scores, leading to a higher mean for Group B when compared to Group A. Choice A is incorrect because Group A is not negatively skewed and doesn't have a mean less than Group B. Choice B is incorrect as Group A is not positively skewed and its mean is not greater than Group B. Choice D is also incorrect because Group B having a mean less than Group A contradicts the fact that Group B has a higher mean due to being negatively skewed.

Correct Answer: A

Rationale: In the study, 60% of 5,000 respondents using smartphones for email would equal 3,000 respondents, not the total number of respondents. Therefore, the correct answer is 3,000 respondents. Choice B, 2,500 respondents, is incorrect because it doesn't consider the percentage of smartphone users. Choice C, 5,000 respondents, is incorrect as it represents the total number of respondents, not the specific number using smartphones for email. Choice D, 1,000 respondents, is incorrect as it is not the correct calculation based on the given information.

Correct Answer: A

Rationale: To simplify the expression 5 x 3 · 9 x 4, first perform the multiplications and divisions from left to right: 5 x 3 = 15 and 9 x 4 = 36. So, the expression becomes 15 · 36. When dividing fractions, multiply the first fraction by the reciprocal of the second fraction. Hence, 15 · 36 = 15/36. To simplify the fraction further, find the greatest common divisor, which is 3. Divide both the numerator and denominator by 3 to get the final result: 15/36 = 5/12. Therefore, the correct answer is A. Choices B, C, and D are incorrect because they do not represent the correct simplification of the given expression.

Correct Answer: D

Rationale: To find the sale price after a 30% discount, you need to subtract 30% of the original price from the original price. 30% of $472 is $141.60. Subtracting this discount from the original price gives $472 - $141.60 = $330.40, which is the sale price Gordon paid. Choice A, $141.60, is incorrect as it represents only the discount amount, not the final sale price. Choices B and C are also incorrect as they do not account for the correct calculations of the discount and final sale price.

Correct Answer: A

Rationale: To simplify the expression, begin by adding 1.034 and 0.275, which equals 1.309. Then, subtract 1.294 from the sum: 1.309 - 1.294 = 0.015. Therefore, the correct answer is 0.015. Choice B (0.15) is incorrect as it does not reflect the accurate calculation. Choice C (1.5) is incorrect as it is not the correct result of the expression simplification. Choice D (-0.15) is incorrect as it represents a different value than the correct outcome of the expression simplification.