Consumption of alcoholic beverages by young women of drinking age has been incre

Question

Consumption of alcoholic beverages by young women of drinking age has been increasing in the United Kingdom, the United States, and Europe (The Wall Street Journal, February 15, 2006). Data (annual consumption in liters) consistent with the findings reported in The Wall Street Journal article are shown for a sample of 20 European young women.

Assuming the population is roughly symmetric, construct a 95% confidence interval for the mean annual consumption of alcoholic beverages by European young women (to 1 decimal).

Explanation / Answer

Sample size (n) =20 European young Women

If we find out the class interval then first we know the sample mean , standard deviation .

Sample Mean (x) = sum of sample / n

sum of sample = 202+82+199+174+97+170+222+115+130+169+164+114+101+171+0+93+0+93+110+374

=2780

x= 2780/20

= 139

Before find out the Standard Deviation we should find out the variance.

Variance (2) = ((202-139)2+(82-139)2+(199-139)2+(174-139)2+(97-139)2+(170-139)2+(222-139)2+(115-139)2+(130-139)2+(169-139)2+(164-139)2+(114-139)2+(101-139)2+(171-139)2+(0-139)2+(93-139)2+(0-139)2+(93-139)2+(110-139)2+(374-139)2)/20 = 125872/20 = 6293.6

Standard Deviation () = 6293.6 = 79.33....

= 79

Formula of Confidence Interval(CI) = X bar ± Z/n ( X bar= mean )

z got from Z table and its value is 1.960

= 139 ± 1.960*79/20

CI = 139 ± 34.62(margin of error)

Upper Bound = 173.62

Lower Bound = 104.38

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