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.)