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Normal Distribution

Standard Normal Distribution or Z Score

A small post-production company re-masters soundtracks for movies and television shows, through a process that tries to minimize reading errors on the final master DVD copy. This population of master DVDs will have errors that are normally distributed, with a mean of µ = 3.5 errors/DVD and a standard deviation of σ = 1.75

Budget director wants to compare travel expense for sales

See attached file for clarity. Ms. Lisa Monnin is the budget director for Nexus Media, Inc. She would like to compare the daily travel expenses for the sales staff and the audit staff. She collected the following sample information. Sales ( $ ) 129 135 148 160 135 144 Audit ( $ ) 125 110 132 134 142 123 133 Us

Standard normal curve, car towing calls, new curriculum

Please provide step by step solution. Instructions: Solve the following problems keep the guidelines below in check. If you are calculating something using a table, the number of decimal places from the table is expected. like z=1.00, table value is .8413 (2 decimal places for z, 4 for the probability) REGARDING NUMBER


1. Last year, at Northern Manufacturing Company, 200 people had colds during the year. One hundred fifty-five people who did no exercising had colds, while the remainder of the people with colds were involved in a weekly exercise program. Half of the 1,000 employees were involved in some type of exercise. a. What is the proba

Plot and Analyze Data: Absorbance for the Iron-Bipyridyl Complex

Please see attached file for the data. The following data were collected on absorbance for the iron-bipyridyl complex as a function of iron concentration in parts per million. Seven groups undertook the experiment. Question 1 In Excel calculate the mean and associated 95%CL for each concentration and then plot these dat

Statistics: Normal Distribution, Rule, Normal Body Temperature

1. Which of the following statements are correct? a. A normal distribution is any distribution that is not unusual. b. The graph of a normal distribution is bell-shaped. c. If a population has a normal distribution, the mean and the median are not equal. d. The graph of a normal distribution is symmetric. Using the 68-

Statistics: Investment Digest for mean of annual return for common stocks

Please provide answers and explanations in Excel spreadsheet. 1. According to Investment Digest ("Diversification and the Risk/Reward Relationship", Winter 1994, 1-3), the mean of the annual return for common stocks from 1926 to 1992 was 15.4%, and the standard deviation of the annual return was 24.5%. During the same 67-

Typical Seasonal Demand for Summer Highs

1. Compute the standard deviation in Microsoft Excel using the data (raw data from years 1-4) 2. Generate a normal distribution of the data using Microsoft Excel. 3. Compare the range with the standard deviation of the data. Typical Seasonal Demand for Summer Highs Actual Demands (in units) Month Year 1


A recent report in BusinessWeek indicated that 28 percent of all employees steal from their company each year. (Round z-score computation to 2 decimal places and your final answers to 4 decimal places.) If a company employs 50 people, what is the probability that: (a) fewer than 9 employees steal? (b) more than 9

Normal Distribution, Z-Score and Percentage

Suppose a botanist grows many individually potted eggplants, all treated identically and arranged in groups of four pots on the greenhouse bench. After 30 days of growth, she measures the total leaf area Y of each plant. Assume that the population distribution of Y s approx. normal with mean=800cm^2 and SD=90cm^2. a) What per

Estimating the first-time customers from a random sample

The president of Doerman Distributors, Inc., believes that 26% of the firm's orders come from first-time customers. A simple random sample of 80 orders will be used to estimate the proportion of first-time customers. Assume that the president is correct and p = 0.26. What is the sampling distribution for this study? Select

8 Statistics problems: Discrete Distributions and Continuous Distributions

This project is based on Discrete Distributions and Continuous Distributions. Question # 7 does not have to be an elaborate study, just something basic, a study that you might conduct at work. 1. What are the characteristics of a normal distribution? 2. Determine the probability or area for the portions of the normal distr

Normal Distribution of mean height of males: probability

Write a paragraph about the normal distribution. In the paragraph give an example of a distribution that you would judge to be nearly normal and explain why you have made that conclusion. Estimate the mean of this distribution and the standard deviation. Then estimate a probability based upon those values: (E.g., average height

Probabilities based on normal distribution.

In a study of how external clues influence performance, psychology professors at the University of Alberta and Pennsylvania State University gave two different forms of a midterm examination to a large group of introductory psychology students. In one form of the exam the questions were printed on blue paper, and in the othe

Statistics: 6 practice problems

1. For a normal distribution, find the z-score values that separate A. The middle 60% of the distribution from the 40% in the tails. B. The middle 70% of the distribution from the 30% in the tails. C. The middle 80% of the distribution from the 20% in the tails. D. The middle 90% of the distribution from the 10% in the tail

Statistics Problems: Normal Distribution, Central Limit Theorem

See attached file. #1. Z is N 17. I distributed. Find (a) P( Z < .6); (b) P( Z <= -.03); (c) P( .12 < Z <= 2.14); (d) P( -1.67 <= Z < 1.20) #2. X is N -10.16 distributed. Find (a) P(X> -12); (b) P(-ll < X <= -8); (c) P(IX+ 101<2); (d) P(IX+lll> 1.5) #4. Suppose that the length X of a random bolt produced by machine A

Weston Materials: Determining Z Values

Please post in Excel Format. Each response must include your calculations. The accounting department at Weston Materials, Inc., a national manufacturer of unattached garages, reports that it takes two construction workers a mean of 32 hours and a standard deviation of 2 hours to erect the Red Barn model. A

Normal Distribution: Raw scores

Suppose we have a population of scores with a mean (mu) of 200 and a standard deviation (sigma) of 10. Assume that the distribution is normal. Provide answers to the following questions: 1. What score would cut off the top 5 percent of scores? 2. What score would cut off the bottom 5 percent of scores? 3. What scor

General Statistics Probability for Cumulative Distribution

1. The age of cars in the staff parking lot of a suburban college is uniformly distributed from six months (0.5 years) to 9.5 years. a) What is being measured here? Age of cars b) In words, define the Random Variable X. c) Are the data discrete or continuous? continuous d) The interval of values for X is: (0.5, 9.5) e) The

Normal distribution department of health

According to the South Dakota Department of Health, the mean number of hours of TV viewing per week is higher among adult women than men. A recent study showed women spent an average of 34 hours per week watching TV and men 29 hours per week ( Assume that the distribution of hours watc

Sampling distribution for means and sums

In exercise 6.8 we considered an automobile insurer whose repair claims averaged $927 over the past with a standard deviation of $871. A random sample of 50 new claims is taken. a. Describe the sampling distribution for ?. b. Use normal approximation to calculate P(? > 1100). The ? is a capital with a line above. I thi

Statistics - Multiple Choice Questions

1. On an exam with s = 6, Tom's score of X = 54 corresponds to z = +1.00. The mean for the exam must be m = 60. (Points: 1) True False 2. A population with m = 45 and s = 8 is standardized to create a new distribution with m = 100 and s = 20. In this transformation, a score of X = 41 from the original distr

Population Mean Corresponding

6. For a population with a mean of µ =100 and standard deviation of Ï? =10, a. X =105 X=120 X = 130 X = 90 X = 85 X =60 b. Find the score (X value) that corresponds to each of the following z-scores. z = 1.00 z = -0.50 z = 2.00 z = 0.70 z = 1.50

Statistics: Multiple Choice Questions

1. An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is know to be $1,000. A random sample of 50 individuals resulted in an average income of $15,000. What sample size would the economist need to use if he wants a 95% confidence interval no wider than plu

Normal Distribution

A) What is normal distribution? b) given a certain data set, how can you determine whether the data set is normally distributed or not? c) Why do we want to test if the data is normally distributed?