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An investment project is expected to earn $100,000 on average with a standard deviation of $50,000. Assume the earnings from this investment project is a normal distribution. What is the probability
find a 99%. confidence interval for the difference between the average grades for the two courses. Assume the populations to be approximately normally distributed with equal variances.
In a management trainee program, 80 percent of the trainees are female, 20 percent male. Ninety percent of the females attended college, 78 percent of the males attended college. A management traine
If one employee is randomly selected, find the decimal probability (four decimal places) that his/her commute takes the following amount of time.
You have the assignment of designing color codes for different parts. Three colors are to be used on each part, but a combination of three colors used for one part cannot be rearranged and used to i
The first card selected from a standard 52-card deck was a king. If it is returned to the deck, what is the probability that a king will be drawn on the second selection?
Estimate is too low for households in Omaha (claim p 0.64). Can the value 0.64 be rejected if a survey of 495 homes in Omaha yields 332 with one or more lawn mowers? Use = 0.05.
Output from a problem contains 0.02 defective units. Defective units that go undetected into final assemblies cost $25 each to replace. An inspection process, which would detect and remove all defec
The mean amount spent by a family of four on food per month is $500 with a standard deviation of $75. Assuming that the food costs are normally distributed, what is the probability that a family spe
A metal fabricator produces connecting rods with an outer diameter that has a 1 +/- 0.01 inch specification. A machine operator takes several sample measurements over time and determines the sample
Probability of 0.4, is won by Spassky with probability of 0.3, and is a draw with probability of 0.3, independently of the previous games. What is the probability that Fischer wins the match?
The mean score of a college entrance test is 500; the standard deviation is 75. The scores are normally distributed. What percent of the students scored below 320?
Does achieving a high grade in reading cause an individual to earn a high grade in Statistics? Explain your answer with reference to the term lurking variable.
A new extended-life light bulb has an average service life of 750 hours, with a standard deviation of 50 hours. If the service life of these light bulbs approximates a normal distribution, about wha
An analysis of the grades on the first test in Statistics 101 revealed that they approximate a normal curve with a mean of 75 and a standard deviation of 8. The instructor wants to award the grade o
Suppose that the mortgage payments of all homeowners have a normal distribution. What is the mean monthly mortgage paid by all homeowner?
Focus groups of 10 people are randomly selected to discuss products of the Famous Company. It is determined that the mean number (per group) is 4.80000019 and the standard deviation is 0.73. Would
Calculate the average percent change for the 9 months of 2006 and the 4 months of 2007. Compare the two averages. What do these measurements indicate about the price index in each time period?
Adam would like to buy a used car, and collected several data to evaluate the best model (such as age, price, weight, etc.) Thanks to a scatterplot, he established that the relation between age, and
A single box contains 12 gloves, and it has been determined that 6 percent of gloves are defective. What is the likelihood that a box of gloves gets rejected?
To research the claim, a random sample of 28 reps revealed that the mean number of calls made last week was 42. The standard deviation of the sample was computed to be 2.1 calls. At the .05 level of
If 280 different quarters are inserted into the vending machine, what is the expected number of rejected quarters?
Find the mean and the standard deviation. Would it be unusual for a sample of 800 to contain 455 jawbreakers that weigh more than .4 ounces?
If measurements of the specific gravity of a metal can be looked upon as a sample from a normal population having a standard deviation of 0.04, what is the probability that the mean of a random samp
Find the mean and standard deviation for the numbers of boys in groups of 51. b) Is the result of 39 boys unusual? Does it suggest that the gender-selection method appears to be effective?