Question

select the correct answer. twenty students in class a and 20 students in class b were asked how many hours they took to prepare for an exam. the data sets represent their answers. class a 2,5,7,6,4,3,8,7,4,5,7,6,3,5,4,2,4,6,3,5 class b 3,7,6,4,3,2,4,5,6,7,2,2,2,3,4,5,2,2,5,6 which statement is true for the data sets? a. the mean study time of students in class a is less than students in class b. b. the mean study time of students in class b is less than students in class a. c. the median study time of students in class b is greater than students in class a. d. the range of study time of students in class a is less than students in class b. e. the mean and median study time of students in class a and class b is equal.

Explanation:

Step1: Calculate mean of Class A

Mean of Class A = $\frac{2 + 5+7+6+4+3+8+7+4+5+7+6+3+5+4+2+4+6+3+5}{20}=\frac{100}{20} = 5$

Step2: Calculate mean of Class B

Mean of Class B = $\frac{3+7+6+4+3+2+4+5+6+7+2+2+2+3+4+5+2+2+5+6}{20}=\frac{80}{20}=4$

Step3: Arrange data of Class A in ascending order

$2,2,3,3,3,4,4,4,4,5,5,5,5,6,6,6,7,7,7,8$
Since $n = 20$ (even), median of Class A=$\frac{5 + 5}{2}=5$

Step4: Arrange data of Class B in ascending order

$2,2,2,2,2,2,3,3,3,4,4,4,5,5,5,6,6,6,7,7$
Since $n = 20$ (even), median of Class B=$\frac{4+4}{2}=4$

Step5: Calculate range of Class A

Range of Class A = $8 - 2=6$

Step6: Calculate range of Class B

Range of Class B = $7 - 2 = 5$

Answer:

B. The mean study time of students in Class B is less than students in Class A