Question

The Quick Change Oil Company has a number of outlets. The numbers of oil changes at the Oak Street outlet in the past 20 days are as follows:

46	47	67	88	41	56	62	70	88	64
38	37	48	65	64	32	57	39	75	89

The data are to be organized into a frequency distribution.

a. How many classes would you recommend?

b. What class interval would you suggest? (Round the final answer to the nearest whole number.)

c. What lower limit would you recommend for the first class?

d. Organize the information into a frequency distribution and determine the relative frequency distribution. (Round the final answers to 2 decimal places.)

Units	Frequency	Relative frequency
30 to under 42
42 to under 54
54 to under 66
66 to under 78
78 to under 90
Total

e. Comment on the shape of the distribution. (Enter the intervals in ascending order.)

The greatest concentration is in classes up to and up to .

Answer 1

Solution:-

a.) ans:

No. of data points=20.

Use:- 2^k >= n , for Number of classes, Here n= no. of data points

=>2^k>=20

Hence, K=5

so, No. of Classes=5 ...ans

b.)Min value=32

max value=89

Class interval (width)=(89-32)/5

=11.4

so class width=12 ...ans

c.)Lower class limit=30

d.)

Units	Frequency	Relative frequency
30 to under 42	5	0.25
42 to under 54	3	0.15
54 to under 66	6	0.30
66 to under 78	3	0.15
78 to under 90	3	0.15
Total	20	1

e. )

From the above distribution we can say the shape is Skewed (Not Symmetric ).