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Normal Distribution

Question about Normal Distributions and Z-Scores

Assume that the average annual salary for a worker in the United States is $27500 and that the annual salaries for Americans are normally distributed with a standard deviation equal to $6250. Find the following: a) What percentage of Americans earn below $18000? b) What percentage of Americans earn above $40000?

Solving a Normal Distribution Problem

What are the characteristics of the normal distribution? Why is the normal distribution important in statistical analysis? Provide an example of an application of the normal distribution.

Z-Scores, Percentile, and Normal Distributions

The diameters of oranges in a certain orchard are normally distributed with a mean of 5.26 inches and a standard deviation of 0.50 inches. a. What percentage of the oranges in this orchard have diameters less than 4.5 inches? b. What percentage of the oranges in this orchard is larger than 5.12 inches? c. A random sample


Federal Government conducts 86,991 pre-employment tests on job applicants engaged in safety and security-related jobs and found that 1,143 were positive. a) Construct 95% confidence interval for population proportion of positive drug tests. b) Why is the the normality assumption not a problem, despite the small value of p?

Description of standard normal random variable

Let z be a standard normal random variable and calculate the following probabilities: p(z is greater than .73) = p(z is less than or equal to 1.75 = p(-1.33 is less than z which is less than 2.2) =

Sampling Distribution of the Sample

Please answer and fully explain the below question: Under what condition, if any, is it not possible for us to assume that the sampling distribution of the sample mean is approximately normally distributed?

Normal Approximation and Binomial Probability

Please help with the following problem. Past experience indicates that 30% of all individuals entering a certain store decide to make a purchase. Using (i) the binomial distribution and (ii) the normal approximation to the binomial, find that probability that 10 or more of the 30 individuals entering the store in the given h

Probability Statements and Regression Data

See the attached file. 3. Spring-loaded canons are designed to shoot t-shirts into the stands at sporting events. Test firings are conducted on a large level field. The distance that a t-shirt flies is a function of the angle of elevation. When the angle is 35 degrees, the distances follow a normal distribution with a mean of

The number of passengers

The number of passengers on the Carnival Sensation during one-week cruises in the Caribbean follows the normal distribution. The mean number of passengers per cruise is 1,820 and the standard deviation is 120. a. What percent of the cruises will have between 1,820 and 1,970 passengers? b. What percent of the cruises will hav

Test Scores and Normal Distribution

Please refer to the attached question. Suppose test scores are normally distributed. What is the best choice for µ and σ , if the average score is 60 and 30% of the scores are over 73?

Probability Using Normal Distribution of SAT Scores

25. The College Board American College Testing Program reported a population mean SAT score of µ 1020 (The World Almanac 2003). Assume that the population standard deviation is 100. a. What is the probability that a random sample of 75 students will provide a sample mean SAT score within 10 of the population mean? b. What

Business Management - Audit Analysis and Statistics.

Can and how would you apply basic probability concepts to facilitate business decision making? What is the difference between discrete and continuous probability distributions? How would you apply the normal distribution to facilitate business decision making?

Martin Pullin Inventory Plan Calculations

I need your help in checking my caculation the attached inventory plan table for Martin-Pullin Bicycles Corp. My other calcualtions on the case are also included on the spreadsheet, I now need to calculate the inventory table, (there are two tabs on the spreadsheet). The key thing is to set up the inventory plan correctly, a mon

Crouse Fuse Company: Business + STATs = Operations Management

The Crouse Fuse Company case (attached pdf) presents a problem that may be analyzed with the use of P-Control Charts. The sampling data from operations during the monitored control week are used as a basis for P-Control chart limits in the future. From the data in Exhibit 1 of the case, there are 80 different samples of 5

Normal Distribution and and Cereal Containers

The amount of cereal in a box is not constant, but the distribution can be modeled with a normal distribution with a mean of 16.5 ounces. If the manufacturer is required to fill 90% of the containers with 16 (or more) ounces of cereal, what is the largest allowable value of the standard deviation ?

Probability - Hotels

A survey for Hotels asked respondents "When traveling internationally, do you generally venture out on your own to experience culture, or stick with your tour group and itineraries?" The survey found that 23% of the respondents stick with their tour group. A. In a sample of 6 international travelers, what is the probability t

Normal Distribution and Z Scores

The distribution of scores on a standardized aptitude test is approximately normal with a mean of 520 and a standard deviation of 100. What is the minimum score needed to be in the top 15 percent on this test? Carry your intermediate computations to at least four decimal places, and round your answer to the nearest integer.

Normal Distribution statistics

Describe how the following frequency table was prepared. Check several of the intervals to see if you get the same frequency. Frequency distribution of ages (at last birthday) of 400 HIV positive men, San Francisco Reported age limits Frequency (fi ) 20-24 2 25-29 85 30-34 135 35-39 91 40-44 57 45-49

Probability Functions in Excel

Here are tables of the Standard Normal and Student's t distributions. The formulas for the first value in each P column are, respectively =NORMSDIST(A3) and =TDIST(C3,20,2), where column A is the one labeled "Z" and column C is labeled "t". I need some help in finding the meaning of the number given in the P column under NORM

Calculating Probability from Normal Distribution

Risk taking is an important part of investing. In order to make suitable investment decisions on behalf of their customers, portfolio managers give a questionnaire to new customers to measure their desire to take financial risks. The scores on the questionnaire are approximately normally distributed with a mean of 50.5 and a st

Probability Concepts & Discrete & Continuous Distributions

NB:Please use Excel(where possible--preferred) for this and could you send me a few notes with step by step break-down on how to make it easy to figure out next time? refer to the real estate excel data set at : http://highered.mcgraw-hill.com/sites/0073030228/student_view0/index.html (see Real Estate Attachment ) Qu

Importance of normal distribution to Statistics

"Why is the Normal Distribution so important to statistics?" Hint 1: Do many real world situations tend to be normally distributed? Hint 2: is the normal distribution used frequently in statistics texts? Hint 3: Is the normal distribution (or its special case, the standard normal distribution) effective in characteriz

Statistics Discussion Questions

What is the difference between Paramaeter & Statistics What is the concept of operationalize???? What are focus groups What is the meaning of lodging double variable, validity & liability Explain Normal Distribution What is mean, median mode What is range & dispersion What the independent & dependent variable Explain e