QNT 561 FINAL EXAM – QUESTION AND ANSWERS

QNT 561 FINAL EXAM – QUESTION AND ANSWERS If x is a binomial random variable with n=10 and p=0.8, what is the probability that x is equal to 4? • .0055 • .0063 • .232 • .994 • .124 The weight of a USB flash drive is 30 grams and is normally distributed. Periodically, quality control inspectors at Dallas Flash Drives randomly select a sample of 17 USB flash drives. If the mean weight of the USB flash drives is too heavy or too light the machinery is shut down for adjustment; otherwise, the production process continues. The last sample showed a mean and standard deviation of 31.9 and 1.8 grams, respectively. Using  = 0.10, the appropriate decision is _______. • fail to reject the null hypothesis and do not shut down the process) do nothing • fail to reject the null hypothesis and shut down the process • reject the null hypothesis and shut down the process • reject the null hypothesis and do not shut down the process Consider the following null and alternative hypotheses. Ho:  ≤ 67 Ha:  > 67 These hypotheses _______________. • indicate a one-tailed test with a rejection area in the left tail Catherine Chao, Director of Marketing Research, is evaluating consumer acceptance of a new toothpaste package. Her staff reports that 17% of a random sample of 200 households prefers the new package to all other package designs. If Catherine concludes that 17% of all households prefer the new package, she is using _______. • a range estimate • a point estimate • an exact estimate • a statistical parameter • an interval estimate Suppose a population has a mean of 400 and a standard deviation of 24. If a random sample of size 144 is drawn from the population, the probability of drawing a sample with a mean less than 402 is _______. • 0.6826 • 0.8413 • 0.1587 • 0.9875 • 0.3413 A large industrial firm allows a discount on any invoice that is paid within 30 days. Of all invoices, 10% receive the discount. In a company audit, 10 invoices are sampled at random. The probability that fewer than 3 of the 10 sampled invoices receive the discount is approximately_______________. •