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Jennifer wants to find a 95% confidence interval for the time it takes her to get...

Jennifer wants to find a 95% confidence interval for the time it takes her to get to work. She kept records for 30 days and found her average time to commute to work was 20.5 minutes with a standard deviation for the population of 3.9 minutes. Jennifer's margin of error would be 1.4 minutes TRUE OR FALSE?

Math   Statistics-And-Probability   
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Answer #1

Solution :

Given that,

= 20.5

= 3.9

n = 30

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z/2 = Z0.025 = 1.96

Margin of error = E = Z/2* ( /n)

= 1.96 * (3.9 / 30)

= 1.4

Margin of error = 1.4

TRUE

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