Answer
a) Q1= 37, Q2(median) = 44, Q3 = 48, Interquartile range = 11, The value 49 fall in the 3rd quartile.
b. 52
c. 70%
Work Step by Step
a. $Q2(median)= ( 20th \& 21th ) /2 = 44, Q1 = (1\div4\times40)th = 10th = 37, Q3= (3\div4\times40)th = 30th = 48,$
Interquartile Range = Q3-Q1 = 48-37= 11,
The value 49 fall in the 3rd quartile .
b. Percentile (91st) = $20\times(91\div100) = 36th = 52$. Around 91% of the days the number of text messages sent by the school student is less than 52.
c. Percentile of 40 or higher = $(28\div40)\times100 = 70%$
c. 70%
