ety researcher is studying the design of a freeway sign and is interested in the mean maximum distance at which drivers are able to read the sign. The maximum distances (in feet) at which a random sample of 16 drivers can read the sign are as follows: 460 550 660 600 600 660 300 500 420 660 250 460 550 600 500 550 The mean of the sample of 16 distances is 520 feet with a standard deviation of 121 feet. (a) What assumption must you make before constructing a confidence interval?
A highway safety researcher is studying the design of a freeway sign and is interested in the
460 550 660 600 600 660 300 500 420 660 250 460 550 600 500 550
The mean of the sample of 16 distances is 520 feet with a standard deviation of 121 feet.
(a) What assumption must you make before constructing a confidence interval?
1) The population distribution is Uniform.
2) The population distribution is Normal.
(b) At the 90% confidence level what is the margin of error on your estimate of the true mean maximum distance at which drivers can read the sign.
Answer=_________ feet (round to the nearest whole number)
(c) Construct a 90% confidence
Lower value=_______ feet (round to the nearest whole number)
Upper value= _______feet (round to the nearest whole number)
(d) There is a 10% chance the error on the estimate is bigger than what value?
Answer=______ feet (round to the nearest whole number)
(e) The researcher wants to reduce the margin of error to only 13 feet at the 90% confidence level. How many additionaldrivers need to be sampled? Assume the sample standard deviation is a close estimate of the population standard deviation.
Answer=_______
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