Tutorial 4

Tutorial 4 1. Compute the mean of the following population values: 7, 5, 7, 3, 7, 4 2. a) Compute the mean of the following sample values :5, 9, 4, 10 __   x − x  =0 b) Show that ∑    3. Compute the mean of the following sample values: 1.3, 7.0,3.6, 4.1, 5.0 _   x − x   =0 b) Show that ∑   4. Compute the mean of the following sample values: 16.25, 12.91,14.58 5. Compute the mean hourly wage paid to carpenters who earned the following wages $15.40, $20.10, $18.75, $22.76, $30.67, $18.00 For Exercise 6until 9: a). Compute the arithmetic mean b). Indicate whether it is statistic or a parameter 6. There are 10 salespeople employed by moody Insurance Agency in Venice, Florida. The numbers of new life insurance policies sold last month by the respective salespeople were : 15, 23, 4, 19, 18, 10, 10, 8, 28, 19 7. The accounting department at a mail-order company counted the following numbers of incoming calls per day to the company’s toll-free number during the first 7 days in May 2003: 14, 24, 19, 31, 36, 26, 17 8. The Cambridge Power and light Company selected a random sample of 20 residential customers. Following are the amounts, to the nearest dollar, the customers were charged for electrical service last month: 54 67 48 68

58 39 50 35

25 56 47 66

75 33 46 62

60 65 70 67

9. The Human Relations Director at Ford began a study of the overtime hours in in the inspection Department. A sample of 15 workers showed they worked the following number of overtime hours last month. 13 6 13 7

12 12 15 10

7 9 15 13

5 12 12

10.The ages of a sample of Canadian tourist flying from Toronto to Hong Kong were : 32, 21, 60, 47, 54, 17, 72, 55, 33, 41

a). Compute the range b). Compute the mean Deviation c). Compute the standard deviation. 11.Creek Ratz is a very popular restaurant located along the coast of northern Florida They serve variety of steak and seafood dinners. During the summer beach season, they do not take reservations or accept “call a head” seating . Management of the restaurant is concerned with the time a patron must wait before being seated for dinner. Listed below is the wait time, in minutes for the 25 tables seated last Saturday night. 28 51 64 39 45

23 44 24 67 65

37 61 29 28 27

24 40 61 28 34

44 25 27 56 50

a). Explain why the times are a population b). Find the mean and median of the times c). Find the range and the standard deviation of the times. a). The Manager of the local Wal-Mart Super Store is studying the number of items purchased by customers in the evening hours. Listed below is the number of items for a sample of 30 customers 15 12 5 8 4

6 6 7 11 9

8 14 9 12 5

4 10 6 18 10

6 10 11 5 10

9 13 12 13 5

a). Find the mean and median of the number of items. b). Find the range and the standard deviation of the number of items