Privacy and information sharing. Refer to the Pew Internet & American Life Project Survey (January 2016), Exercise 4.48 (p. 239). The survey revealed that half of all U.S. adults would agree to participate in a free cost-saving loyalty card program at a grocery store, even if the store could potentially sell these data on the customer’s shopping habits to third parties. In a random sample of 250 U.S. adults, let x be the number who would participate in the free loyalty card program.
a. Find the mean of x. (This value should agree with your answer to Exercise 4.48c.)
b. Find the standard deviation of x.
c. Find the z-score for the value x = 200.
d. Find the approximate probability that the number of the 250 adults who would participate in the free loyalty card program is less than or equal to 200.
Referring to the Paw Internet & American Life Project Survey (January 2016), exercise 4.48.
x be the participate in the free loyalty card program, which follows a binomial distribution with n = 250 and p = 0.5
Therefore, the mean of x is 125.
Therefore, the variance of x is 7.9057.
The z-score is,
Therefore, the z-score is 9.4868.
Therefore, the approximate probability is 1.
Gender discrimination suit. The Journal of Business & Economic Statistics (July 2000) presented a case in which a charge of gender discrimination was filed against the U.S. Postal Service. At the time, there were 302 U.S. Postal Service employees (229 men and 73 women) who applied for promotion. Of the 72 employees who were awarded promotion, 5 were female. Make an inference about whether or not females at the U.S. Postal Service were promoted fairly.
4.139 Load on timber beams. Timber beams are widely used inhome construction. When the load (measured in pounds) perunit length has a constant value over part of a beam, the loadis said to be uniformly distributed over that part of the beam.Uniformly distributed beam loads were used to derive thestiffness distribution of the beam in the American Institute of
Aeronautics and Astronautics Journal (May 2013). Considera cantilever beam with a uniformly distributed load between100 and 115 pounds per linear foot.
a. What is the probability that a beam load exceeds110 pounds per linearfoot?
b. What is the probability that a beam load is less than102 pounds per linear foot?
c. Find a value L such that the probability that the beamload exceeds L is only .1.
Which of the following describe discrete random variables, and which describe continuous random variables?
a. The number of damaged inventory items
b. The average monthly sales revenue generated by a salesperson over the past year
c. Square feet of warehouse space a company rents
d. The length of time a firm must wait before its copying machine is fixed
Stock market participation and IQ. Refer to The Journal of Finance (December 2011) study of whether the decision to invest in the stock market is dependent on IQ, Exercise 3.46 (p. 182). Recall that an IQ score (from a low score of 1 to a high score of 9) was determined for each in a sample of 158,044 Finnish citizens. Also recorded was whether or not the citizen invested in the stock market. The accompanying table gives the number of Finnish citizens in each IQ score/investment category. Which group of Finnish citizens (market investors or noninvestors) has the highest average IQ score?
Invest in market
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