The Wall Street Journal reported that automobile crashes cost the United States

Question

The Wall Street Journal reported that automobile crashes cost the United States $162 billion annually (The Wall Street Journal, March 5, 2008). The average cost per person for crashes in the Tampa, Florida, area was reported to be $1599. Suppose this average cost was based on a sample of 50 persons who had been involved in car crashes and that the population standard deviation is $600.

*PLEASE CHECK ANSWERS A, B, D, AND E. ALSO, WHAT IS THE ANSWER TO C?*

a. What is the margin of error for a 95% confidence interval? ANS: 166

b. What would you recommend if the study required a margin of error of $150 or less? ANS: A sample size of 62

c. What is the point estimate for the population mean? ANS: ?

d. What is the standard error of the sample mean implied by the information in this question? ANS: 84.8528

e. What is the margin of error to 4 decimal places? ANS: 166.3085

Explanation / Answer

here std error =std deviation/(n)1/2  =600/(50)1/2 =84.85

for 95% CI, z=1.95996

hence margin of errorr =z*std error =166.3085

b)for sample size =(z*std deviation/E)2 =(1.96*600/150)2 =~62

c) point estimate =1599

d) standard error of the sample mean =600/(50)1/2 =84.85

e)hence margin of errorr =z*std error =166.3085

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