What are the rules to solving equations by multiplying or dividing?
1 answer:
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Answer:
Step-by-step explanation:
Given that confidence level is 95% and sample mean is within 10 minutes of the population mean. i.e. margin of error = 10
Std deviation of population= 211 minutes
Margin of error = Z critical * std error
Std error = sigma/sq rt n =
Hence we have
\frac{211}{\sqrt{n} }
The minimum sample size is 1710
a) There may not be 1,809 computer users to survey
Answer:
84%
Step-by-step explanation:
The empirical rule tells you that 68% of the standard normal distribution is within 1 standard deviation of the mean. The distribution is symmetrical, so the amount in the lower tail is (1 -68%)/2 = 16%.
Since the number you're interested in, 240, is one standard deviation above the mean (200 +40), the percentage of interest is the sum of the area of the central part of the distribution along with the lower tail:
68% + 16% = 84%.
