The director of admissions at Kinzua University in Nova Scotia estimated the distribution of student admissions for the fall semester on the basis of past experience
The Internal Revenue Service is studying the category of charitable contributions. A sample of 28 returns is selected from young couples between the ages of 20 and 35 who had an adjusted gross income of more than $100,000. Of these 28 returns, 5 had charitable contributions of more than $1,000. Suppose 4 of these returns are selected for a comprehensive audit.
According to the "January theory," if the stock market is up for the month of January, it will be up for the year. If it is down in January, it will be down for the year. According to an article in The Wall Street Journal, this theory held for 28 out of the last 34 years. Suppose there is no truth to this theory; that is, the probability it is either up or down is 0.5.
Customers experiencing technical difficulty with their internet cable hookup may call an 800 number for technical support. It takes the technician between 150 seconds and 14 minutes to resolve the problem. The distribution of this support time follows the uniform distribution
A normal population has a mean of 21 and a standard deviation of 6.
Assume that the hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,100 per hour and a standard deviation of $250.
The manufacturer of a laser printer reports the mean number of pages a cartridge will print before it needs replacing is 12,400. The distribution of pages printed per cartridge closely follows the normal probability distribution and the standard deviation is 620 pages. The manufacturer wants to provide guidelines to potential customers as to how long they can expect a cartridge to last.
A study of long-distance phone calls made from General Electric Corporate Headquarters in Fairfield, Connecticut, revealed the length of the calls, in minutes, follows the normal probability distribution. The mean length of time per call was 5.20 minutes and the standard deviation was 0.70 minutes.
A population consists of the following five values: 13, 15, 17, 19, and 22.
The mean age at which men in the United States marry for the first time follows the normal distribution with a mean of 24.4 years. The standard deviation of the distribution is 2.6 years. For a random sample of 57 men, what is the likelihood that the age at which they were married for the first time is less than 24.9 years? (Round z value to 2 decimal places. Round your answer to 4 decimal places.)