Chapter 5 Test
Assume that when human resource managers are randomly selected, 59% say job applicants should follow up within two weeks. If 30 human resource managers are randomly selected, find the probability that exactly 22 of them say job applicants should follow up within two weeks.
.0425 binompdf ( 30, .59, 22)
Groups of adults are randomly selected and arranged in groups of three. The random variable x is the number in the group who say that they would feel comfortable in a self-driving vehicle. Determine whether a probability distribution is given. If a probability distribution is given, find its mean and standard deviation. If a probability distribution is not given, identify the requirements that are not satisfied. x P(x) 0 0.359 1 0.435 2 0.178 3 0.028
0 .359, 0, 0 1 .435, .435, .435 2 .178, .356, .712 3 .028, .084, .252 mean = 0 + .435 + .356 + .084 = .875 = .9 standard deviation = sqrt((.435+.712+.252) - (.875)^2) = .795 = .8
Based on a poll, among adults who regret getting tattoos, 29% say that they were too young when they got their tattoos. Assume that nine adults who regret getting tattoos are randomly selected, and find the indicated probability. Complete parts (a) through (d) below. a. Find the probability that none of the selected adults say that they were too young to get tattoos. b. Find the probability that exactly one of the selected adults says that he or she was too young to get tattoos. c. Find the probability that the number of selected adults saying they were too young is 0 or 1. d. If we randomly select nine adults, is 1 a significantly low number who say that they were too young to get tattoos?
A. .0458 (9, .29, 0) B. .1685 (9, .29, 1) C. .0458 + .1685 = .2143 D. No, because the probability that at most 1 of the selected adults say that they were too young is greater than 0.05.
Determine whether the following value is a continuous random variable, discrete random variable, or not a random variable. a. The amount of rainfall in a country in a year b. The usual mode of transportation of people in City A c. The weight of a hamburger d. The number of people with blood type B in a random sample of 44 people e. The time it takes for a light bulb to burn out f. The time it takes to drive from City A to City B
A. Continuous random variable B. Not random variable C. Continuous random variable D. Discrete random variable E. Continuous random variable F. Continuous random variable
Assume that when human resource managers are randomly selected, 43% say job applicants should follow up within two weeks. If 13 human resource managers are randomly selected, find the probability that fewer than 3 of them say job applicants should follow up within two weeks.
The probability is . 0370 bionompdf( 13, .43, 2) + bionompdf( 13, .43, 1) + bionompdf( 13, .43, 0)
When purchasing bulk orders of batteries, a toy manufacturer uses this acceptance sampling plan: Randomly select and test 60 batteries and determine whether each is within specifications. The entire shipment is accepted if at most 2 batteries do not meet specifications. A shipment contains 6000 batteries, and 1% of them do not meet specifications. What is the probability that this whole shipment will be accepted? Will almost all such shipments be accepted, or will many be rejected?
The probability that this whole shipment will be accepted is .9776 The company will accept 97.76% of the shipments and will reject 2.24% of the shipments, so almost all of the shipments will be accepted
For 100 births, P(exactly 56 girls)=0.0390 and P(56 or more girls)=0.136. Is 56 girls in 100 births a significantly high number of girls? Which probability is relevant to answering that question? Consider a number of girls to be significantly high if the appropriate probability is 0.05 or less.
The relevant probability is P(56 or more girls), so 56 girls in 100 births is not a significantly high number of girls because the relevant probability is greater than 0.05.
Assume that hybridization experiments are conducted with peas having the property that for offspring, there is a 0.75 probability that a pea has green pods. Assume that the offspring peas are randomly selected in groups of 30. Complete parts (a) through (c) below. a. Find the mean and the standard deviation for the numbers of peas with green pods in the groups of 30. b. Use the range rule of thumb to find the values separating results that are significantly low or significantly high. c. Is a result of 5 peas with green pods a result that is significantly low? Why or why not?
a. mean = 22.5 (.75*30) standard deviation = 2.4 sqrt(22.5(1-.75)) b. 17.7 sign low 22.5-2.4-2.4 27.3 sign high 22.5+2.4+2.4 c. The result is sign low, because 5 peas with green pods is less then 17.7 peas
The accompanying table describes the random variable x, the numbers of adults in groups of five who reported sleepwalking. Complete parts (a) through (d) below. a. Find the probability of getting exactly 4 sleepwalkers among 5 adults. b. Find the probability of getting 4 or more sleepwalkers among 5 adults. c. Which probability is relevant for determining whether 4 is a significantly high number of sleepwalkers among 5 adults: the result from part (a) or part (b)? d. Is 4 a significantly high number of 4 sleepwalkers among 5 adults? Why or why not? Use 0.05 as the threshold for a significant event. x P(x) 0 0.153 1 0.434 2 0.252 3 0.127 4 0.033 5 .001
a. .033 b. .034 p(4)+P(5) c. Since the probability of getting 4 or more sleepwalkers is the probability of the given or more extreme result, the result from part (b) is the relevant probability. d. Yes, since the appropriate probability is less than 0.05, it is a significantly high number.
A survey showed that 32% of human resource professionals are at companies that rejected job candidates because of information found on their social media. If 24 human resource professionals are randomly selected, would 13 be a significantly high number to be at companies that rejected job candidates because of information found on their social media? Why or why not?
Yes, 13 would be significantly high because the probability of 13 or more is 0.0202, which is low.
