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Normal Distribution


Confidence Interval Estimation 2. Compute a 95% confidence interval for the population mean, based on the sample 15, 17, 13, 14, 15, 14, and 59. Change the number from 59 to 14 and recalculate the confidence interval. Using the results, describe the effect of an outlier or extreme value on the confidence interval.

Plot the vehicle stopping distance versus the speed of travel

Question 1 The distance Y necessary for stopping a vehicle is a function of the speed x of the vehicle. Suppose the following set of data were observed for 12 vehicles travelling at different speeds as shown in the table below. Vehicle No. Speed, kph Stopping Distance, m 1 40 15 2 9 2 3 100 40 4 50 15 5 15 4 6 65 25

Research and Evaluation: Example Problem

What are some examples of literature reviews and statistics used and available at your work place or organization? What are they used for and how are they determined? What are the advantages and disadvantages of using surveys to conduct research? What is an example of a loaded question? In what situations is it appropriate t

Consider a random variable, z, that has a standardized normal distribution. Determine the following probabilities: Bowser Bites Industries (BBI) sells large------standard deviation of 1.25 kilograms. What is the probability that a filled bag will weigh less than 49.5 kilograms?

Can you please assist with questions 6-11 and 6-17 putting the answers and solutions in an excel spread sheet. 6.11 ) Consider a random variable, z, that has a standardized normal distribution. Determine the following probabilities: a) P(0<z<1.96) b) P(z>1.645) c) P(1.28<z<2.33) d) P(-2<z<3) e) P(z>-1) 6.17 ) Bow

Problems with Normal Distribution

Amazing Bakers sells bread to 40 supermarkets. It costs Amazing $1,250 per day to operate its plant. The profit per loaf of bread sold in the supermarket is $.025. Any unsold bread is returned to the Amazing Thrift Store to be sold at a loss of $.015. a. If sales follow a normal distribution with µ = 70,000 and &#61555; =

Internet hookup, insurance spending, 3 songs, home loans

1. Customers experiencing technical difficulties with their internet cable hook up may call 800 numbers for technical support. It takes the technician between 30 second to 10 minutes to resolve the problem. The distribution of this support time follows the uniform distribution. a. what are the values for a and b in minutes?

Multiple choice questions and answers

Suppose a population consisted of 20 items. How many different samples of n = 3 are possible? A. 1140 B. 6840 C. 20 D. 120 The difference between the sample mean and the population mean is called the A. Population standard deviation. B. Population mean. C. Standard error of the mean. D. Sa

Normal Distribution: Tax Preparation Fees

In 1999, the average charge for tax preparation by H&R Block, Inc. was $84.57. Assuming a normal distribution and a standard deviation of o = $10, what proportion of H&R Block's tax preparation fees were. a. more than $84.57? b. between $64.57 and $104.57? c. between $74.57 and $94.57? d. more than $104.57?

Normal Probabilities: Serum Cholesterol Levels in Men

You may find the probabilities using the Table or software of your choice. Please explain how you obtained your results. The serum cholesterol levels in men aged 18-24 are normally distributed with a mean of 178.1 and a standard deviation of 40.7. Units are mg/100 mL, and the data are based on the National Health Survey.


1) Describe how scale impacts the interpretation of a graph 2) Name the lowest number of a statistically significant sample size 3) State the statistically appropriate percentage total of displays 4) Explain how mean, median, and mode are applied to categorical and numerical data 5) List the characteristics of a normal bel

An expert response to: Normal Probability

Chapter 7, problem 37 - The net sales and the number of employees for aluminum fabricators with similar characteristics are organized into frequency distributions. Both are normally distributed. For the net sales, the mean is $180 million and the standard deviation is $25 million. For the number of employees, the mean is 1,500 a

Z scores

6.18 Many manufacturing processes use the term work-in-process (often abbreviated as WIP). In a book manufacturing plant, the WIP represents the time it takes for sheets from a press to be folded, gathered, sewn, tipped on end sheets, and bound. The following data (stored in the file wip.xls) represent samples of 20 books at eac

Statistics Practice Test: 7 questions about sixth graders

See attached files. Download the file entitled "elementary.xls." This file contains data on the 100 6th grade students at Oceanview Elementary School in Wichita, Kansas. Use this data to answer the questions below. Unless otherwise noted, use the 5% confidence level for all calculations. 1. Describing the Data a) Ident

Normal distributions: Probabilities and percentiles

The highway police in a certain state are using aerial surveillance to control speeding on a highway with a posted speed limit of 55 miles per hour. Police officers watch cars from helicopters above a straight segment of this highway that has large marks painted on the pavement at 1-mile intervals. After the police officers obse

Stochastic Inventory Model: An Example

A bagel shop buys each bagel for .08 and sells each bagel for .35. Leftover bagels at the end of they day are purchased by a local soup kitchen for .03 per bagel. The shop owner has observed daily demand (Q), the following probabilities (F(Q) Q=0, F(Q)= .05 Q=5, F(Q)= .1 Q= 10 F(Q)= .1 Q= 15, F(Q)= .2 Q= 20, F(Q)= .25

Activity Estimation Constructions

Suppose the following estimates of activities (in weeks) for the construction of a swimming pool were provided, along with their immediate predecessors. What is the probability that the project will be completed within 21 weeks? Within 22 weeks? Activity A B C D

Estimating Mean Percent Change in Population

1. Bone loss by nursing mothers. Breast-feeding mothers secrete calcium into their milk. Some of the calcium may come from their bones, so mothers may lose bone mineral. Researchers measured the percent change in mineral content of the spines of 47 mothers during three months of breast-feeding. Here are the data: -4.7

Six Sigma Computation and Interpretations

To what probabilities do each of the following sigma levels correspond to, based on a standard normal curve: 3 sigma, 4sigma, 5 sigma, and 6 sigma? (Hint: Use the NORMSDIST function in Excel. Note that this function returns the standard normal cumulative distribution function. The distribution has a mean of 0 (zero) and a standa

Normal Distribution and Probability

Shelia's doctor is concerned that she may suffer from gestational diabetes (high blood glucose levels during pregnancy). There is variation both in the actual glucose level and in the blood test that measures the level. A patient is classified as having gestational diabetes if the glucose level is above 140 milligrams per decili

Paired Difference Test

A paired difference experiment produced the following results a) Determine the values of z for which the null hypothesis, m1 -m2 = 0, would be rejected in favor of the alternative hypothesis, m1 - m2 < 0. Use a = 0.10 b) Conduct the paired difference test described in part a. Draw the appropriate conclusions. c) What assump

Advanced probability and Statistics

1.Suppose a normal distribution has u =1.4,and o =0.2, calculate the z -score f or x= 3.5 2.What is the mode of the data set 23, 44, 22, 23, 23, 44, 23, 55? 3. Give the following data set 50, 40, 33, 37, 60 a. Find the mean, median and mode b. Find the standard deviation

Normally distributed - Population Mean & SD

1. Assume that each energy type is produced by a process that is normally distributed and calculate the population mean and SD from the entire data set (1980 -2005). 2. Determine the probability that next year's production will exceed production in 1990 for each type. Year Coal 2 Natural Gas 3 Crude Oil 4 Nuclear Electric

Case Study

Practice Problem: At the age of 42 Enrique Chavez was starting thinking more and more about retirement. After 17 years of running one of the bay area's tattoo parlor he decided to take on a partner - his 21 year old bilingual niece Diana. Her words still echoed in his head - the same words she repeated every time someone left h

Normal distribution

1200 males students average height was 5 feet 7 inches with a std. Deviation of 5 inches. If heights are distributed normally what is the expected number of students that are. A. Greater than 6 feet tall b. Between 5 feet and 6 feet.

Frequency Numbers for Data Representations

The data represents the daily rainfall (in inches) for one month. Construct a frequency distribution beginning with a lower class limit of 0.00 and use a class width of 0.20. Does the frequency distribution appear to be roughly a normal distribution? 0.39 0 0 0.29 0 0.54 0 0.17 0 0 1.25 0 0.16 0 0.02 0 0.21 0 0.13 0.46 0

Mean and Normal Distribution

A machine cuts plastic into sheets that are 30 feet (360 inches) long. Assume that the population of lengths is normally distributed. a) The company wants to estimate the mean length the machine is cutting the plastic within 0.25 inch. Determine the minimum sample size required to construct a 90% confidence interval or the

What is the standard error of the mean in this experiment?

The Oil Price Information Center reports the mean price per gallon of regular gasoline is $3.26 with a population standard deviation of $0.18. Assume a random sample of 40 gasoline stations is selected and their mean cost for regular gasoline is computed. a. What is the standard error of the mean in this experiment? b. Wha