The back-to-back stem-and-leaf plot below show exam scores from two different math classes. Which class has a greater mean score
2 answers:
Answer:
B. greater mean = class B greater median = class B
Step-by-step explanation:
Stem and Leaf Plots : It is a special table where each data value is split into a stem (the first digit or digits) and a leaf (usually the last digit).
So, in the given plot for class A
The first stem 4 has leafs = 1,5
The numbers will be 41,45
The second stem 5 has leafs = 1,6,8
The numbers will be 51,56,58
The third stem 6 has leafs = 5,7,7,9
The numbers will be 65,67,67,69
The fourth stem 7 has leafs = 6,6,7,8,9
The numbers will be 76,76,77,78,79
The fifth stem 8 has leafs = 1,2
The numbers will be 81,82
The sixth stem 9 has leafs = 1
The number will be 91
So, The data of class A = 41,45,51,56,58,65,67,67,69,76,76,77,78,79,81,82,91
Thus MEAN of class A = Sum of all scores scored by students / Total No of students whose marks are given
⇒
Thus mean of class A = 68.17
Median =The "median" is the "middle" value in the list of numbers.
Since 9th term is the middle value .
So, MEDIAN of class A = 69
The given plot for CLASS B :
The first stem 4 has leafs = 2
The numbers will be 42
The second stem 5 has leafs = 4
The numbers will be 54
The third stem 6 has leafs = 1,6
The numbers will be 61,66
The fourth stem 7 has leafs = 2,5,6,6
The numbers will be 72,75,76,76
The fifth stem 8 has leafs = 0,0,4,8,9
The numbers will be 80,80,84,88,89
The sixth stem 9 has leafs = 3,5,6,7
The number will be 93,95,96,97
So, The data of class B = 42,54,61,66,72,75,76,76,80,80,84,88,89,93,95,96,97
Mean of class B =
⇒
⇒
Thus mean of class B is 77.88
Median of class B = 9th term = 80
Hence , mean of class A = 68.17 and median of class A = 69
Mean of class B = 77.88 and median of class B = 80
Thus Option B is correct .
Greater mean = class B
Greater median = class B
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