First Data Corp records indicate that in 2005 43 of adult em

First Data Corp. records indicate that in 2005 43% of adult email users received a phishing email. A phishing email replicates an authentic site for the purpose of stealing personal information such as account numbers and passwords. Suppose a random sample of 800 adults will be surveyed on whether they have received phishing emails to determine recent trends. Use this information to answer questions 1 through 3.

First Data Corp. records indicate that in 2005 43% of adult email users received a phishing email. A phishing email replicates an authentic site for the purpose of stealing personal information such as account numbers and passwords. Suppose a random sample of 800 adults will be surveyed on whether they have received phishing emails to determine recent trends. Use this information to answer questions 1 through 3. Give the mean and standard deviation of the sample distribution of hatp. Give your answers in decimal form. (Example: 0.398) Mean (Round to two decimal places) = Standard deviation (Round to three decimal places) = Determine the probability that more than 45% of those in a survey would have received a phishing email. What is the z-score for a 45% probability? (round to three decimal places, Example: 3.456) z = What is the probability that more than 45% of those in a survey would have received a phishing email? Give your answer in decimal form, rounding to three decimal places. (Example: 0.398)

Solution

Sample proportion = 45% = 0.45

Mean of sample distribution = p hat = 0.43

variance = 0.43(0.57)/800

std dev =0.0175

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z statistic for >45% = 1.143

P(p>45%) = P(Z>0.02/0.0175) =0.5-0.3729

= 0.1271

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2) z statistic for >45% = 1.143

3) P(p>45%) = 0.1271