46 



SUMMARIZATION OF DATA 



Ch. 2 



4. Determine the median and also the upper limits of the first and third 

 quartiles for the data of problem 1 when all results are considered as one group 

 of data. Ans. 28.0, 27.95, 28.22. 



5. Take any newspaper which gives quotations from New York bond prices 

 and make frequency and r.c.f. distributions for all the closing prices as listed 

 for that particular day. 



6. Graph the distributions for problem 5. Then determine graphically the 

 proportion of the prices which exceed 100. Check this result by actual count. 



You are given the following information as a basis for working problems 7 

 to 11, inclusive. These data are from the Ohio Psychological Tests given to 

 602 students at Kansas State College during 1945. The scores are represented 

 by the symbol X in the following summary, and are given only as integers: 



7. Make the r.c.j- distribution and graph it. 



8. Compute approximations to n and a 2 after changing the top and bottom 

 classes to 111-117, and 13-19, respectively. Ans. 58.6, 423.0. 



9. What percentage of the students had scores above 100? Between 50 and 

 75? What range of scores is included between the 80th and 90th percentiles? 



10. Graph the frequency distribution and state which average you would 

 employ to convey the best impression of the level of performance by these 

 students on this standard test. 



11. If 30 scores were to be selected at random from these 602, how many of 

 them would you expect to fall at or below 40? 



12. Given that N = 25, 2F = 110, and 2F2 = 600 for any particular set of 

 measurements, calculate the coefficient of variation. Ans. 48.9 per cent. 



13. Given the following frequency distributions for a certain group of prices 

 of bonds, construct graphs of these distributions. Briefly describe the sorts 

 of information which can be obtained from such figures, and give several 

 illustrations. 



Total 500 



