Given,
The stem and leaf plot of the data is shown in question.
The first statement is median is 30.
Here, the median of the data is 30.
Hence, statement 1 is correct.
The second statement is that the number of student who read less than 20 pages are 10.
But the number of student who reads less than 20 pages are 4.
Hence, statement 2 is also incorrect.
The third statement is over 50% of students read less than 20 pages
Here,
total number of students are 20.
The number of student who can read only pages less than 20 are 4.
4 is 20% of 20.
Hence, statement 3 is also incorrect.
The forth statement is the range of the data is 52.
Range= larger value - smaller value
= 67 - 12
= 55
Here, the range of the given data is the 55.
Hence, statement 4 is not correct.