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Determine the mean and standard deviation of the random variable X. (round to nearest penny).
What is the probability that a sample of 50 female grads will provide a sample mean within $.50 of the population mean, $18.80? What is the prob. that a sample of 120 female graduates will provdie a s
Suppose that the distribution of net typing rate in words per minute (wpm) for experienced typists can be approximated by a normal curve with mean 54 wpm and standard deviation 15 wpm. (Round all an
1. A random variable has possible values of 20, 21, 22, 23, and 24 that are equally likely to occur. a) What is the probability that the random variable is less than 23? b) What is the mean of the ran
Suppose a geyser has a mean time betwen eruptions of 83 minutes. Let the interval of time between the erupitons be normally distributed with standard deviation 24 minutes.
Construct a stem-and-leaf plot for these data. Arrange the leaves for each stem in increasing order. What is the shape of the stem-and-leaf plot, symmetric, skewed to the left or skewed to the right?
What is the expected number of trees sold in the month of December? What is the standard deviation of the number of trees sold in the month of December?
In a recent survey, ten percent of the homes in Montana were found to own a Miley Cyrus action figure. In a sample of ten homes:
A system is composed of eight independent subsystems. Each subsystem operates 95% of the time. What is the probability that all the subsystems are operating at any random point in time?
Fatal errors that require a system reboot occur an average of 7 times per week. (The system runs 24 hours a day, 7 days a week.) The number of fatal errors can be adequately modeled by a Poisson dis
The claim that the proportion of adults who smoked a cigarette in the past week is less than .30, and the sample statistics include n=1093 subjects with 350 saying that they smoked a cigarette in th
The Comfort Widget Company makes several different sized widgets. The smallest widget the company manufactures has a mean diameter of 2.35 inches with a standard deviation of .25 inches. The distr
A company wants to check the consistency of electronic copies of signatures for consumer credit purchases. A sample of 49 electronic signatures are available from the same customer.
Let X denote the amount of time in hours a book on two-hour reserve is actually checked out, and suppose the cdf is
The rate of return for na investment can be described by a normal distribution with mean 47% and standard deviation 3%. What is the probability that the rate of return for the investment exceeds 53%
A new phone answering system for a company is capable of handeling seven calls every 10 minutes. Prior to installing the new system, company analyst determined that the incoming calls to the system
Among nine nominees for three vacancies on a city council are five men and four women. In how many ways can these vacancies be filled
A random sample of 12 second-year university students enrolled in a business statistics course wasdrawn. At the course's completion, each student was asked how many hours he or she spent doinghomewo
A study found that 41% of assisted reproductive technology (ART) cycles resulted in pregnancies. Twenty-six precent of the ART pregnancies resulted in multiple births.
Suppose 40% of the vehicles passing through a toll booth are trucks and the rest are cars. A truck pays a $5 toll whereas a car pays $3. Find the expected revenue from the next vehicle that passes thr
A Bright Idea. A company produces lightbulbs whose life follows the N(1500; 300) distribution, i.e. the lifetimes of lightbulbs have a normal distribution with a mean of 1500 hours and a standard de
Weekly demand at a grocert store for a brand of cereal is normally distributed according to X ~ N (800 boxes, 75^2 boxes)
For each of the following, find the probability for the given normal distirbution:
A random sample of 35 GMAT scores for applicants to an MBA program has a mean score of 479. The researcher is interested in finding evidence at the .05 level that the mean score of applicants to the