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Standard Deviation

Standard deviation is a measure of absolute variation used to calculate the amount of divergence which exists from an expected value and is denoted by the Greek symbol for sigma. Out of all the measures of dispersion and spread, standard deviation is the most frequently utilized and it is advantageous in that it can easily detect for skewness (1).

The variables in this equation are:
σ = standard deviation (in this equation it is denoted by the letter s)
x = each value in the population
xbar = mean of sample
n = number of scores



Testing the Difference Between Two Sample Means

Please describe the process and paste the output. List the description to enable me generate mine output. Please remember the assignment is using SPSS not excel. You may refer also to Posting 622444 Library Download on Fundamental Statistics One Sample Mean in which the author answered same questions using excel. I have adde

Find confidence interval using standard normal distribution

Q1 You are a proprieter of NYC boutique. You want to know the average age of your customers. You take a random sample of 25 customers which yields an average age of 32 yrs with a standard deviation of 8. You have reason to belive the distibution of ages is normally distributed. Determine a 95% confidence interval for the age

Computing and analyzing the simple regression equation

Enterprise Industries produces Fresh, a brand of liquid laundry detergent. In order to study the relationship between price and demand for the large bottle of Fresh, the company has gathered data concerning demand for Fresh over the last 30 sales periods ( each sales period is four weeks). Here, for each sales period, y = dem

Computing mean, variance and standard deviation

1) Please calculate the standard deviation, mean, and variance for the dataset below (round to the nearest 2 decimal places where applicable). Men's 400 Meter Race Athlete Country Time LaShawn Merritt USA 43.75 Jeremy Wariner USA 44.74 David Neville USA 44.80 Chris Brown BAH 44.84 Leslie Djhone FRA 45.11 Ma

ES, LS, ED and LF and slack time

13.5 Calculate ES, LS, EF, LF and slack time for activities in Exercise 13.1 (see attached file for data) 13.1 Given the diagram shown in figure ex 13.1, with activities A through G and duration times (see attached file for data)

Cronbach's Alpha - Calculation and Interpretation using SPSS

Calculate Cronbach's alpha on the scale provided on pp. 710-711 of the Field text using the SAQ.sav file. Here is the scale provided on pp, 710-711 of the Andy Field text book: 1 Subscale 1 (Fear of statistics): items 1, 3, 4, 5, 12, 16, 20, 21 2 Subscale 2 (Peer evaluation): items 2, 9, 19, 22, 23 3 Subscale 3 (Fear of co

Project Management: PERT Network Diagram

The information presented in Table 1 represents the optimistic activity time (a), most probable activity time (m), and pessimistic activity time (b) in weeks for each activity associated with the project. See attached file for table 1. 1. What is the expected activity time (t) in weeks for each activity? Enter this infor

Management and Statistics

Please provide a short review of concepts and examples of: sample, measures of central tendency (mean value), and measure of variation (range, standard deviation σ) related to business management. In addition, could you show how these various elements are determined mathematically.

Calculating Standard Deviations

5.The credit manager of a discount sports equipment store believes that the average age of his charge account customers is 30 years. His deputy contends that the average age is less than 30 years. A random sample of 100 charge account customers showed the mean age as 27 years with a standard deviation of 10 years. Do these data

Cusum Chart

The data in the following table are individual temperature readings from a chemical process in oC, taken every two minutes (read in sequence top to bottom and left to right). The target value for the mean is 950 oC. (a) Estimate the process standard deviation. (b) Set up and apply a tabular cusum chart for this process, using

Distribution of Systolic Blood Pressure: The 68-95-99.7 Rule

How do I break-down this problem to find the best possible answer? What is the 68-95-99.7 rule? The systolic blood pressure of a group of 18-year-old women is normally distributed with a mean of 120 mmHg and a standard deviation of 12 mmHg. What percent of 18-year-old women in this group have a systolic blood pressure betwee

Observed significance level

For each of the below questions (1, 3, 5), determine the observed significance level. How would I do this? 1. The data below represents a random sample of weights (in grams) from a batch of a particular product. The nominal value is 87.5 grams. Prove that this sample is consistent with the nominal value, to a 90% confidence

Statistics: Manufacturer's Claims

A manufacturer claims that a particular kind of solar shade can reduce the ambient temperature by 2 degrees centigrade over traditional materials. Over random times over several days, temperatures were taken at the same time under a traditional awning and an adjacent awning using this brand of solar shade. In the attachment, c

Sample Statistics Problems

1. A survey of 400 people who took vacations revealed that 242 of them flew to their destination. Give a 95% confidence interval for the percentage of all people who fly when they take a trip. Does it appear statistically correct to conclude that more than 50% of all people who take vacations will fly to their destination? Why

Verifying the process to compute this problem

I am trying to determine the range and standard deviation of the following data: 1.9950,2.01667, 2.01883, 2.01983, 2.02000, 2.02267, 2.03333. 2.03333, 2.034, 2.03616, 2.03667, 2.04000, 2.04000, 2.04433, 2.04583, 2.05000, 2.05000, 2.05333, 2.06000, 2.06767, 2.07417 How do I compute the range and the std deviation?

Statistics problem on weights

Assume the weight of a product is normally distributed with a mean of 1.5 and a variance of 0.2. What percentage of products will have weights within +/- 3 standard deviations? What are the lower and upper limits bounding 50% of product weights? Determine the weight where no more than 1% of all products will exceed that amoun

Determining Statistics or Parameters

The personnel director of a corporation will study the overtime work during the previous year for the 2,575 clerical workers. A sample of 100 of these workers will be chosen at random from the files. The average and the standard deviation of the overtime hours will be calculated and the number of these employees who worked more

Calculating security risk

Security A has an expected return of 7 percent, a standard deviation of expected returns of 35 percent, a correlation coefficient with the market of -0.3 and a beta coefficient of -0.5. Security B has an expected return of 12 percent, a standard deviation of returns of 10 percent, a correlation with the market of 0.7 and a beta

Data sample

The data below include the temperature data from a period of 20 days. find this data sample,calculate the rang, the mean deviation,variance and standard deviation 77 68 65 54 64 53 79 53 52 79 50 73 74 63 73 72 53 54 52 75

4 Books, Calculate the Mean and Standard Deviation.

Please show ALL steps. On your shelf, you have four books that you are planning to read in the near future. Two are fictional works, containing 212 and 379 pages, respectively, and the other two are non -fiction, with 350 and 575 pages respectively. (a) Compute the population mean  and standard deviation  of the (paren

standard deviation calculation and mean

To get the best deal on a CD player, Tom called eight appliance stores and asked the cost of a specific model. The prices he was quoted are listed below: $ 298 $ 125 $ 511 $ 157 $ 231 $ 230 $ 304 $ 372 How would you find the standard deviation?

Gallup Organization released results of a poll comparing lifestyles

On January 7, 2000, the Gallup Organization released the results of a poll comparing lifestyles of today with those yesteryears. Then poll results were based in telephone interviews with a randomly selected national sample of 1,031 adults, 18 years and older, conducted December 20-21, 1999. One question asked if the respondent h

standard deviation and its implication

What does standard deviation measure? In looking at the standard deviations of the "with fireplace" and "without fireplace" selling prices, one is much larger than the other. What could cause the standard deviations to be so different?

Statistics: Standardized scores

A distribution with a mean of 38 and a stand deviation of 20 is being transformed into a standardized distribution with mean of 50 and standard deviation of 10 find the new standardized score for each of the following scores from the original population. X= 48 X= 30 X= 40 X= 18

Could you explain how to use Covariance?

6*. Estimates of the expected returns, standard deviations and correlation coefficients for the possible rates of return on three stocks are: *Please see attachment. (b) If equal investments are made in all three stocks, what is the expected return and the standard deviation of the return from the portfolio? v(w)

Six Sigma Analysis

1. A company makes a part with a diameter of 1 inch with a tolerance of plus or minus .005 of an inch. The process has a mean of 0.997 and a standard deviation of 0.001 inch. Is the process capable? Why or why not? 2. A company owns a lease granting it the right to explore for oil on a property. The company may sell the l

A new weight-watching company, Weight Reducers International, advertises that those who join will lose, on the average, 10 pounds the first two weeks with a standard deviation of 2.8 pounds. A random sample of 50 people who joined the new weight reduction program revealed the mean loss to be 9 pounds. At the .05 level of significance, can we conclude that those joining Weight Reducers on average will lose less than 10 pounds? Determine the p-value. Please show step-by-step calculations.

A new weight-watching company, Weight Reducers International, advertises that those who join will lose, on the average, 10 pounds the first two weeks with a standard deviation of 2.8 pounds. A random sample of 50 people who joined the new weight reduction program revealed the mean loss to be 9 pounds. At the .05 level of signifi