Explore BrainMass
Share

# Normal Distribution

### Percentile Rank Standard Score

A set of data is normally distributed with a mean of 100 and standard deviation of 15 · What would be the standard score for a score of 90? · What percentage of scores is between 100 and 90? · What would be the percentile rank for a score of 90?

### 16 Statistics multiple choice questions

10. According to the empirical rule, if the data form a "bell-shaped" normal distribution, ________ percent of the observation will be contained within 1 (one) standard deviation around the arithmetic mean. (Points: 4) 68.26 75.00 88.89 93.75 11. The probability that a new advertising

### Statistics Analysis for Number of Days Americans Take Vacation

The number of days Americans take each year for vacation is normally distributed with a mean of 15.8 days and a standard deviation of 2.2 days. X P(X < x) P(X > x) Mean Std dev 11 .0146 .9854 15.8 2.2 15 .3

### 5 Statistics problems: Normal distribution, probability, mean of sample

The starting salaries of individuals with an MBA degree are normally distributed with a mean of \$40,000 and a standard deviation of \$5,000. What percentage of MBA's will have starting salaries of \$34,000 to \$46,000? The weights of items produced by a machine are normally distributed with a mean of 8 ounces and a standard de

### Statistics: Distances for students from centrally located college

Please help with the following problem. A college is located in the geographic center of mainland United States. The admission officer examines the east-west distance of the college from the hometown of each incoming resident student. Incoming resident students living to the east of the college are scored as + distances, and

### Statistics: Floor to ceiling effect, use of interval, normal distribution

2.22 Would the data for number of murders by those convicted of the crime be an example of a floor or ceiling effect? 2.36. For each of the types of data described below, would you present individual data values or grouped data when creating a frequency distribution? Explain your anwser clearly. (a) eye color observed for 87

### Normal Distribution for Shaver Manufacturing, dental insurance for employees

Solve this by using Appendix B.1 table Shaver Manufacturing, Inc., offers dental insurance to its employees. A recent study by the human resource director shows the annual cost per employee per year followed the normal probability distribution, with a mean of \$1,280 and a standard deviation of \$420 per year. a.) What fra

### Describing the properties of a normal distribution

Describe the properties of a normal distribution. Why are there infinite possible normal distributions? Why should one assume that sample data represents a population distribution?

### Statistics problems

If the mean and the standard deviation of a continuous random variable that is normally distributed are 20 and 5, respectively, find an interval that contains 68% of the distribution. A. (18,24) B. (15,25) C. (12,25) D. (10,30) 2. If the mean and the standard deviation of a continuous random variable that is normally d

### Percent of garages for Weston Materials; Shaver Manufacturing cost of dental insurance.

1) 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. Assume the assembly times follow the normal distribution. a. Determine the z values for 29 a

### Sampling Distribution of Sample Mean: Rapide2010

A small upstart company, Rapide, manufactures high-speed hard drives for laptops. Their new hard drive, the Rapide2010, is manufactured so that the number of reading errors per MB of data forms a normal distribution, with a mean of 4.2 errors / MB and a standard deviation of 1.3 errors / MB. If Bell Computers buys 15 Rapide2

### 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 &#963; = 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

### Mean score on a certain aptitude test across the nation is 100

Assume that the mean score on a certain aptitude test across the nation is 100, and that the standard deviation is 20 points. Find the probability that the mean aptitude test score for a randomly selected group of 150 8th graders is between 97 and 103.

### Statistics: Testing the Diameters of Grapefruits in an Orchard

Question: The diameters of grapefruits in a certain orchard are normally distributed with a mean of 5.82 inches and a standard deviation of 0.61 inches. Show all work. (A) What percentage of the grapefruits in this orchard is larger than 5.78 inches? (B) A random sample of 100 grapefruits is gathered and the mean diameter

### 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

### Bell Shaped Distribution

A random sample of 40 gas stations in Baton Rouge after Hurricane Katrina resulted in a mean price of \$3.02 per gallon with a standard deviation of \$0.07. A histogram of the data indicated that the data followed a bell shaped distribution. A) What percentage of the gas stations have prices that range from \$2.88 to \$3.16 B)

### Statistics

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

### Standard Score for Normal Data

A set of data is normally distributed with a mean of 500 and a standard deviation of 100. Questions: 1. What would be the standard score for a score of 433? 2. What percentage of scores are between 500 and 433? 3. What would be the percentile rank for a score of 433?

### 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

### Shape of the Sampling Distribution of x for General Electric soft-white light bulbs

Show all work The print on the package of 100-watt General Electric soft-white light bulbs claims that these bulbs have an average life of 750 hours. Assume that the lives of all such bulbs have a normal distribution with a mean of 750 hours and a standard deviation of 55 hours. Let x (sample mean) be the mean life of a ran

### Normal Probability: Diameter of a Jar

The diameter of a jar is 3 inches although could be as much a 3.03 inches or as little as 2.97 inches. There were 25 samples of these jars taken with a grand mean of 3.01 inches and a standard deviation of .02 inches. What is the probability of producing a bad product?

### 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-

### Computing Sample Means

Crossett Trucking Company claims that the mean weight of its delivery trucks when they are fully loaded is 6,050 pounds and the standard deviation is 160 pounds. Assume that the population follows the normal distribution.Fifty trucks are randomly selected and weighed. Within what limits will 90 percent of the sample means occ

### Statistics

The mean age at which men in the United States marry for the first time follows the normal distribution with a mean of 24.7 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 25.2 years?

### Operating Cost for the Lowest 4 Percent of the Airplanes

Assume that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of \$2,050 per hour and a standard deviation of \$205. What is the operating cost for the lowest 4 percent of the airplanes? (Round z value to 2 decimal places. Omit the "\$" sign in your response.)

### 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

### 1 question statistics

Best Electronics, Inc. offers a "no hassle" returns policy. The number of items returned per day follows the normal distribution. The mean number of customer returns is 10.4 per day and the standard deviation is 2.3 per day. (a) In what percent of the days are there 7.5 or fewer customers returning items? (Round z-score co

### 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