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Normal Distribution

Sample Sizes, Normal Distribution, and T-Distribution

1. In order to efficiently bid on a contract, a contractor wants to be 99% confident that his error is less than two hours in estimating the average time it takes to install tile flooring. Previous contracts indicate that the population standard deviation o- is 4.5 hours. Find the minimum sample size "n" that is needed to estima

Binomial Probability and Confidence Intervals

(17) A recent study following attrition rates at a major university has shown that 43% of all incoming freshmen do not graduate within 4 years of entrance. If 200 freshmen are randomly sampled this year and their progress is followed, what is the probability that 100 or less will not graduate within the next 4 years. Verify that

Daily output of Marathon's Garyville, Lousiana, refinery is normally distributed with a mean of 232,000 barrels of crude oil per day with a standard deviation of 7,000 barrels.

Daily output of Marathon's Garyville, Lousiana, refinery is normally distributed with a mean of 232,000 barrels of crude oil per day with a standard deviation of 7,000 barrels. (a) What is the probability of producing at least 232,000 barrels? (b) Between 232,000 and 239,000 barrels? (c) Less than 239,000 barrels? (d) Less than

Variables and Normal Distribution

Discuss why you would or would not expect each of the following variables to be normally distributed. Hint:Would you expect a single central mode and tapering tails? Would the distribution be roughly symmetric? Would one tail be longer than the other? a. Shoe size of adult males. b. Years of education of 30-year-old employed

Defining the Normal Curve of Distribution

I have been given the task to study a group of students that are completing their BA degree in psychology. The main purpose of the study is to find out their level of satisfaction and to identify the most helpful areas provided by the program. Based upon this information formulate: Formulate hypothesis for this problem. I

Tire Manufacturing: Normal Distribution and Standard Deviation

A tire manufacturer believes that the tread life of its snow tires can be described as a normal distribution with a mean of 32,000 miles and a standard deviation of 2500 miles. a. If you buy a set of these tires, would it be reasonable to expect they will last 40,000 miles? What do you base your decision on? b. What perce

Probability calculation Using Normal Distribution Problem

Please help with the following question. Provide step by step calculations. Assume that the number of calories in a McDonald's Egg McMuffin is a normally distributed random variable with a mean of 290 calories and a standard deviation of 14 calories. (a) What is the probability that a particular serving contains fewer than 3

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

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) =

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

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 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 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 : (see Real Estate Attachment ) Qu

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

Elementary Statistics: 29 True/False questions & 4 questions

I have attached a Word document that contains 29 True/False questions and 4 questions where you need to figure out 'what is wrong.' TRUE or FALSE - all responses must be at least 25 words! 1. Class width = Upper limit of a class - Lower limit of the same class. 2. A class frequency may be equal to zero. 3. The data 9, 12


An industrial oven used to cure san cores for a factory manufacturing engine blocks for small cars is able to maintain fairly constant temperatures. The temperature range of the oven follows a normal distribution with a mean of 450 F and a standard deviation of 25 F. Leslie Larsen, president of the factory is concerned about t