Explore BrainMass

Standard Deviation

Statistics Questions

X1 X2 The participants were randomly assigned to groups 1 and 2 34 45 32 35 15 32 27 28 20 34 1. t = 2. df = 3. For a ONE TAILED TEST, with p < .05, what is the Tabled Value, and is the above t significant or not significan

Payback Period to Implement New Product

A business currently has a business intelligence tool called WebFocus in a production environment (supporting end users). Cost to maintain WebFocus is $313,832 per year in software maintenance fees and other associated costs to include helpdesk support and other labor. The business wants to migrate from WebFocus to Oracle D

A manufacturing process involved in the production of plastic molds for a specific automotive application is under study. To control the mean thickness of this (normally distributed) process with a standard deviation, s = 3.0, chart is used with n = 5, LCL = 14.15, and UCL = 15.85.

[1] A manufacturing process involved in the production of plastic molds for a specific automotive application is under study. To control the mean thickness of this (normally distributed) process with a standard deviation, s = 3.0, chart is used with n = 5, LCL = 14.15, and UCL = 15.85. If the process means shifts to 15.2, find t

Calculations with Random Samples

Given random samples of size 5 on the tensile strength of a metal part with LSL = 244 and USL = 256, answer the following questions. (a) Calculate the Cp by first estimating the standard deviation of the process. (b) What percentage of the specification band is used by the process?

Methods of Interval Estimation

Discuss how you can apply the concept and method of interval estimation to help you solve some of the problems in a regularly accounting department. Give a few examples.

Statistical stimation of lifetime of a consumer product

Whirltag claims that the useful lifetime of its dishwashers is normally distributed with a mean of 3 years and a standard deviation 1 year. Consumer Rejects magazine tested 25 of these dishwashers and found that the average useful life was only 2.5 years. Using Whirltag's reported 1-year standard deviation, what is Consumer Reje


Find th range, mean, variance, and standard deviation of the sample sata set: 19 20 17 21 21 21 19 18 19 19 17 17 15 18 18 18 18 17 17 17 Range: Sample mean, Rount to the nearest hundredth Sample variance(Unse unrounded values to find the answer, Round to the nearest hundredth) Sample standard deviatio

Finding the mean of a normal distribution of scores

A psychologist has designed a questionnaire to measure individuals' aggressiveness. Suppose that the scores on the questionnaire are normally distributed with a standard deviation of 80. Suppose also that exactly 15% of the scores exceed 700. Find the mean of the distribution of scores. Carry your intermediate computations to at

Maximum Tolerable Error

I am trying to calculate the maximum tolerable error given a sample size. I am given the standard deviation and I have been told that the mean is within 1 of the population mean. Without the actual mean, how can I calculate the maximum tolerable error? I am using: maximum allowable error = (z-value * standard deviation)/sq

Stat Class

#78. Consider a sample x1, x2, ..., xn and suppose that the values of x, s2, and s have been calculated. _ a. Let yi = xi - x for i = 1, ..., n. How do the values of s2 and s for the yi's compare to the corresponding values for the xi's? Explain. _ b. Let zi = (xi - x ) / s

Find Probabilities, Mean and Standard Deviation, and Distribution

1. The number of hours needed by students in an economics course to complete a term paper are attached. A student is selected at random. Find the following probabilities. a. the student took more than 9 hours b. the student took less than 6 hours c. the student took between 7 and 9 hours, inclusive. 2. A box holds 5 bl

Find the standard score

Find the standard score for the value x=452 realative to its sample, where the sample mean is 500 and the standard deviation is 32. Then find the value of x that corresponds to the standard score of 1.2, where the mean is 135 and the standard deviation is 15.

Standard deviation with large variance

Please explain the process to find the standard deviation with a big difference in the seconds, 0,250,0,164,0,519. Please show how to find from this data.

I don't understand this at all please show necessary steps.

Assume that you are the Quality Manager for the Emerson D. Meritz Machine Tool Company. Your model IE566 grinding machine is afflicted by three types of defects classified as major (type A), serious (type B) and minor (type C). You wish to set up a demerit system for this product using the following weighting scheme: D=100

Standard Deviation.

The College Board American College Testing Program reported a population mean SAT score of &#61549; =1017. Assume that the population standard deviation is &#61555; = 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 is the pr

Statistics- probablity distribution

If a balanced die is rolled six times and the outcomes create a unique distribution, perform the following: P(exactly three fives) {Use formula} mean {Use formula} variance {use formula} standard devaiation {use formula} Problem # 2 If 20%

Business forecasting

Dick Hoover, owner of Modern Office Equipment, is concerned about freight costs and clerical costs incurred on small orders. In an effort to reduce expenditures in this area, he has decided to introduce a discount policy rewarding orders over $40 in the hope that this will cause customers to consolidate a number of small orders

Calculating midrange, first quartile, mean, standard deviation

Sixteen retail outlets were surveyed to find the cost of a window chiller. The results are 280,310,265,298,285,325,360,340,260,275,295,280,355,295 and 355. find the midrange find the value corresponding to P50 find the first quartile (in dollars) find the mean find the unbiased standard deviation what is th z-score,

Find Standard Deviation using the computational formula

"My Bank" opens a branchin a commercial district. The bank wants to find out the waiting time of their customers during the Friday evening hours from 5pm to 8pm. Accordingly, the waiting time is recorded for all customers during these hours over a month. A random sample of 20 customers is selected; the waiting time, in minutes,

Comparing the Average Difference and Standard Deviation Between Two Populations

While it cannot be denied that advertising impacts sales, it is also true that advertising is expensive and companies want to advertise in ways that have the greatest benefit for the amount of money spent. A company that sells snack food designs two different advertising strategies, one focusing on print media and the other on r

A statistical excercise in portfolio selection.

An investor has a certain amount of money available to invest now. Three alternative portfolio selections are available. The estimated profits of each portfolio under each economic condition are indicated in below table: Portfolio Selection Event A B

Consider the three values of mean and the three values of standard deviation

I need to know how to do this in EXCEL.. Thank you The question below appears in the attached file as well. You may find it easier to read in the attachment. Given the following population data: 1,2,4,5,8,9,12, and the lists of all samples of size 2 and 5: Samples of n=2 -xbar 1,2--1.5 1,4--2.5 1,5--3 1,8-----------

Softball League Wins

Question: At the end of the season, the number of wins in a softball league for each of the eight teams is: {10, 9, 5, 4, 4, 3, 3, 2) What is the standard deviation of wins?