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(1 point) A recent poll of 2200 randomly selected 18- 25-year-olds revealed that

ID: 3060458 • Letter: #

Question

(1 point) A recent poll of 2200 randomly selected 18- 25-year-olds revealed that 255 currently use marijuana or hashish. According to a publication, 12.5 % of 18-25-year-olds were current users of marijuana or hashish in 1997. Do the data provide sufficient evidence to conclude that the percentage of 18-25- year-olds who currently use marijuana or hashish has changed from the 1997 percentage of 12.5%? Use = 0.05 significance level. test statistic z = positive critical z score negative critical z score The final conclusion is A. There is not sufficient evidence to conclude that the percentage of 18-25-year-olds who currently use marijuana or hashish has changed from the 1997 percentage of 12.5%. B. There is sufficient evidence to conclude that the percentage of 18-25-year-olds who currently use marijuana or hashish has changed from the 1997 percentage of 12.5%.

Explanation / Answer

Test statistic:

pbar = 0.125 , p = 0.1159 , n = 2200

z = ( pbar - p)/ sqrt( p * ( 1 - p) / n)
= ( 0.125 - 0.1159) / sqrt(0.1159 * 0.8841 / 2200)
= 1.332

Positive critical z score = + 1.96

Negative critical z score = - 1.96

The final conclusion is Option A)