7/30/2019 Laundry Case 1[1]

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Laundry statistics

According to Procter & Gamble, 35 billion loads of laundry are run in the United States each year, Every second,

1,100 loads are started. Statistics show that one person in the United States generates a quarter of a ton of dirty

clothing each year. Americans appear to be spending more time doing laundry than they did 40 to manufactures’

innovations in this area. In the United States, the average washing machine uses about 16 gallons of water. In

Europe, the figure is about 4 gallons. The average wash cycle of an American years ago. Today, the average

American woman spends seven to nine hours a week on laundry. However, industry research shows that the result

is dirtier laundry than in other developed countries. Various companies market new and improved versions of 

washers and detergents. Yet, Americans seem to be resistant wash is about 35 minutes compared to 90 minutes in

Europe. Americans prefer top loading machines because they do not have to bend over, and the top loading

machines are larger. Europeans use the smaller front-loading machines because of smaller living spaces.

Managerial and Statistical Questions

Virtually all of the statistics cited here are gleaned from studies or surveys.

1.  Suppose a study of laundry usage is done in 50 U.S. households that contain washers and dryers. Water

measurements are taken for the number of gallons of water used by each washing machine in completinga cycle. The following data are the number of gallons used by each washing machine during the washing

cycle. Summarize the data so that study findings can be reported. 15 17 16 15 16 17 18 15 14 15 16 16 17 16 15 15 17 14 15 16 16 17 14 15 12 15 16 14 14 16 15 13 16 17 17 15 16 16 16 14

17 16 17 14 16 13 16 15 16 15 

2.  The average wash cycle for an American wash is 35 minutes. Suppose the standard deviation of a wash

cycle for an American wash is 5 minutes. Within what range of time do most American wash cycles fall?

3.  Is the amount of laundry done by a household each year related in some way to the household income?

Suppose eight households of two adults and two children are randomly chosen for a study. Over a yearperiod, a record is kept of the weight of clothing washed by each household, and their annual household

income is ascertained. From the following study data, determine whether a relationship exists between a

household’s income and the amount of laundry done (in weight). 

Amount of laundry  Household Income (Weight in ibs.) ($1,000s)

 ______________________________________________________________________________

1,210 42

875 31

1,890 60

1,450 68

2,040 110

1,330 45

660 561,490 72

1,950 93 __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________