1.

In estimating the mean monthly fuel expenditure,, per household vehicle, the U.S. Energy Information Administration takes a sample of size 6486. Assuming that= 20.18 dollars, determine the margin of error in estimatingat the 95% level of confidence.

_____ dollars.

2.

55people are randomly selected and the accuracy of their wristwatches is checked, with positive errors representing watches that are ahead of the correct time and negative errors representing watches that are behind the correct time. The55values have a mean of109 sec.

Assume a population standard deviation of178sec. Use a0.01significance level to test the claim that the population of all watches has a mean of0sec (use a two-sided alternative).

The test statistic is_____

The P-Value is_____

3.

When two lights blink in alternation close together, we perceive one light moving back and forth if the time between blinks is short.

We want to know the longest interval of time between blinks that preserves this illusion of motion? We ask subjects to turn a knob that slows the blinking until they "see" two lights rather than one light moving. A report gives the results in the form "mean plus or minus the standard error of the mean." Data for 17 subjects are summarized as24742(in milliseconds).

What are xand s for these subjects? (This exercise is also a warning to read carefully: that24742isnota confidence interval, yet summaries in this form are common in scientific reports.)

x=______

s= _____

4.

A study of commuting times reports the travel times to work of a random sample of 30 employed adults in New York State. The mean isx= 31.25 minutes and the sample standard deviation is s = 22 minutes. What is the standard error of the mean?

_____

5.

How much money do winners go home with from the television quiz showJeopardy? To determine an answer, a random sample of winners was drawn and the amount of money each won was recorded and listed below. Estimate with 92% confidence the mean winning's for all the show's players.

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