416 411 415 415 420 420 420 420 420 420 (a) show that seven classes would be use

Question

416 411 415 415 420 420 420 420 420 420 (a) show that seven classes would be used to create a frequency distribution for these show that a class interval of 30 would summarize the data in seven classes. (b) frequency distributions for the data with seven classes (c) Construct frequency and relative class lower limit and a class interval 30, the first (d How many home runs traveled a distance of 360 up to 390 feet? feet? (e) What percentage of the home runs traveled a distance of 360 up to 390 (f What percentage of the home runs traveled a distance of 390 feet or more? Exercises 7. A set of data consists of 38 observations. How many classes would you recommend for the frequency distribution? 8. A set of data consists of 45 observations between so and $29. What size would you rec- 9. ommend for the class interval? s567. What class interval of data consists of 230 observations between s235 and would you 10. A set of data contains 53 observations. The minimum value is 42 and the maximum value is The data are to be organized into a frequency distribution. a. How many classes 11. b. What would you suggest the lower limit of the first class? of units in the last Inc. produced the following number This icon indicates data is available at the text website: www.mhte.comMindbasicae, You will be able to download the data directly into Excel or Minitab from this site. 16 days. 27 27 27 28 27 25 25 28 26 28 26 28 31 30 26 26 The information is to be organized into a frequency distribution. a. How many classes would you recommend? b. What class interval would you suggest? c. What lower limit would you recommend for the first class? d. Organize the information into a frequency distribution and determine the relative fre- quency distribution. e. Comment on the shape of the distribution. 12. The Quick Change Oil Company has a number of outlets in the metropolitan Seattle area. The daily number of oil changes at the Oak Street outlet in the past 20 days are: 65 98 55 62 79 59 51 90 72 56 70 62 66 80 94 79 63 73 71 85 The data are to be organized into a frequency distribution. a. How many classes would you recommend? b. What class interval would you suggest?

Explanation / Answer

Answers

Q7

Number of observations is not a consideration when deciding class width and number of classes. These depend on the range of values. There is no definite rule to decide these either. A general rule of thumb is: the number of classes is somewhere between 5 and 10. Steps involved in decision are   1. Find the lowest and highest value 2. Take a convenient value less than the lowest value and again a convenient value greater than the highest value. This will constitute the working range. 3. Divide the working range into 5 - 10 classes so that the range of each class is again a convenient number, say, 2, 5, 10, 20, 50, 100 etc.

Q8

Class width - 5, Number of classes - 6

Q9

Expand the actual range of values from (235 - 567) to (230 - 580) Class width - 50, Number of classes - 7

Q10

Expand the actual range of values from (42 - 129) to (40 - 130)    Class width - 10, Number of classes - 9

Q11

Since the number of observations is small and the range of values is also narrow, a simple frequency distribution with single value per class is recommended. The frequency distribution would be: 25 || 26 |||| 27 |||| 28 |||| 29 - 30 | 31 | It is not advisable to comment of the shape of the distribution when the number of observations is small, say less than 50. Neverthless, the distribution looks Normal.

  

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.