Statistics Confidence Interval Level: High School
The probability is 1 in 4,000,000 that a single auto trip in the United States will result in fatality. Over a lifetime, an average U.S. driver takes 50,000 trips. (a) What is the probility of a fatal accident over a lifetime?Explain your reasoning carefully. Hint: Assume independent events. Why might the assumption of independence be violated?
(b) Why might a driver be tempted not to use a seat belt "just on this trip"?
Statistics Confidence Interval Level: High School
A certain airplane has two independent alternators to provide electrical power. The probability that a given alternator will fail on a 1-hour flight is .02. What is the probability that(a) both will fail?
(b)Neither will fail?
(c) One or the other will fail? Show all steps carefully
Statistics Confidence Interval Level: High School
Why is population shape of concern when estimating a mean? What does sample size have to do with it?
Statistics Confidence Interval Level: High School
State the main points of the Central Limit Theorem for a mean.
Statistics Confidence Interval Level: High School
In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1,143 were positive.(a) Construct a 95 percent confidence interval for the population proportion of positive drug tests.
(b) Why is thenormality assumption not a problem, despite the very small value of p? (Data are from Flying 120, no. 11 [November 1993], p. 31.)
Statistics Confidence Interval Level: High School
A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were 3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477(a) Construct a 90 percent confidence interval for the true mean weight.
(b) What sample size would be necessary to estimate the true weight with an error of ± 0.03 grams with 90 percent confidence?
(c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during manufacture. (Data are from a project by MBA student Henry Scussel.)
