Question 465156
i)z=(121.8-120)/5.6=.321
The area under the normal curve between 0 and .321 is .126 the probability the individual's pressure will be between 120 and 121.8 mm Hg.
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ii) (121.8-120)/(5.6/sqrt(30))
=(1.8/1.022)
=1.761
The area under the normal curve between 0 and 1.761 is .461,  the probability that the sample mean will be between will be between 120 and 121.8 mm Hg.
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Ed