STAT 200 Final Examination, Spring 2017 OL4 US2 (SOLUTIONS) STAT 200 Final Examination | Page 3

(a) Complete the frequency table with frequency and cumulative relative frequency. Express the
cumulative relative frequency to three decimal places.
(b) What percentage of the adults in this sample has an IQ score between 90 and 129,
inclusive?
(c) Which of the following IQ score groups does the median of this distribution belong to?
70 – 89, 90 – 109, or 110 – 129? Why?
4. ​ The five-number summary below shows the grade distribution of a STAT 200 quiz for a
sample of 160 students
Answer each question based on the given information, and ​ explain ​ your answer in ​ each ​ case.
(a) What is the interquartile range in the grade distribution?
(b) Which of the following score bands has the fewest students?
(i) 30 - 50
(ii) 50 - 70
(iii) 70 - 90
(Iv) Cannot be determined
(c) How many students in the sample are in the score band between 50 and 70?