a)13
b) skewed
c) IQR
d)Sam's observation is correct
e)6.17
Step-by-step explanation:
Step 1 :
From the histogram we can infer that
0 to 2 texts has been sent by 1 student
2 to 4 texts has been sent by 3 student
4 to 6 texts has been sent by 4 student
6 to 8 texts has been sent by 4 student
8 to 10 texts has been sent by 5 student
Step 2:
a)
From step 1 , we can see that there are total of 17 students represented by the histogram
Step 3:
b)
This is a skewed histogram because we have all large values of students on the right of the histogram and smaller values on the left of the histogram.
In symmetrical histogram, there would be large values on the center and the smaller values on both sides.
Step 4:
c)
IQR would be better recommendation for this as this is a skewed histogram
Standard deviation would be recommended for a symmetrical histogram
Step 5:
d)
Total number of students is 17
Number of students who text between 8 to 10 messages is 5
Hence the students who text between 8 and 10 messages is 5/17
which is nearly 1/3 rd of the total students.
Hence Sam's observation is correct
Step 6:
e)
Mean amount of the texts = (1 * 3 + 3* 3 + 5*4 +7*4 + 9* 5) /17 = 6.17
and 
, 
.