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Dispersion and Spread of Data

Control Plan Problem

Problem #1 According to the control plan, 8 bolts will be measured every half hour and the machine will will be stopped if it is out of adjustment. Ninety-five percent of the bolts should be within 4+ or - .0004 inches. The last act of 8 showed the following measurements: 4.001 3.998 4.009 3.997 3.990 4.002 3.998

Statistics with Z scores and Bayesian Statistics

1. What is the term Bayesian statistics used to indicate? 2. What are the states of nature? 3. What is a variable? 4. What is a z score? 5. How does a z score differs from a t score? 6. What does the symbol sX represent? 7. What is the symbol for standard deviation? 8. What is one formula that we can use to calcula

Statistics: Arranging Data, Quartiles, Box plot, Mean Problems are attached.

16. Millionaires: The ages of the 36 millionaires sampled are arranged in increasing order in the following table. 31 38 39 39 42 42 45 47 48 48 48 52 52 53 54 55 57 59 60 61 64 64 66 66 67 68 68 69 71 71 74 75 77 79 79 79 a. Determine the quartiles for the data. b. Obtain and interpret the interquartile range.

Gamma Distribution

Suppose that when a transistor of a certain type is subjected to an accelerated life test, the lifetime X (in weeks) has a gamma distribution with mean ... (see attachment)


1. Compute the mean, median, and mode for each of the following distributions. A B C D 3 2 1 2 3 2 3 3 4 2 3 4 6 5 3 4 7 5 5 4 8 7 5 5 10 7 8 7 8 8 8 10 8 8 11 9 11 2. I grew up in a very tiny town in the Midwestern United States. The two had seven streets, and the number of buildings on each street were a

Data Error

In the process of acquiring data for research, we sometimes find ourselves facing possibility that field workers may have intentionally introduced error into the data. (A) Why and how might they have done this? (B) What can we do to prevent such errors?

Standard Deviant - How Large of a Sample

A researcher is interested in the average amount of sugar that kindergarten kids eat per day within 4 grams. In a preliminary sample of 36 kids, the amount consumed ranged from 105 grams to 305 grams. The researcher wants to be 97% confident that the margin of error will not be exceeded. How large of a sample must she do if she

Range, Std. dev., and Variance

The number of cars that travel through an intersection between noon and 1pm is measured for 30 consecutive days. The results of the 30 observations are: 61,62,63,63,64,64,66,66,67,68,68,68,68,69,69,69,69,70,70,70,70,71,71,72,73,74,74,75,76,and 79 Find: a.) Range b.) Standard Deviation c.) The population standar

Box and Whisker Plots

A box and whisker plot is used to display data. Explain what box and whisker plots shows us. Provide example. Thanks.

Portfolio: expectation, standard deviation and covariance

An investor wants to invest 1000 euro. He can choose between the shares of the electronic company Solips and the food supply chain Bhold. The value of the first share is 1 euro at the moment the investment is made, the price of the second share is 2 euro. How should the investor divide the 1000 euro between the two types of shar

Relationship of Mean and Standard Deviation

Please see the attached MS Word Document. It shows a table with three variables and the min, max, mean and SD for the each variable. I'm trying to determine what the rlationship is between the mean and SD for each variable. Introduction to Social Research Methods As part of an assignment I am working on I have the followin

Estimating Mean Germination Time of Strawberry Seeds

Suppose that we want to estimate the mean germination time of strawberry seeds. The germination times for the sample of strawberries we choose has a mean of days and a standard deviation of days. For each of the following sampling scenarios, determine which test statistic is appropriate to use when making inference statements


You are given the following data for the number of times a population of six families dined out during the previous month: 4 6 9 4 5 7 a. Compute the mean, median and mode for this data. b. Compute the range for this data. c. Compute the variance and standard deviation. d. Assume that these data represent a sample rat

Calculating the mean and variance for different portfolios.

Calculating the mean and variance for different portfolios. David wants to invest his $4 million inheritance. He walks into Stock-o-rama and examines the information about four particular stocks. David will sell his stocks after exactly one year. Each of the stocks will pay out a particular amount in one year, times the a

Testing a claim given a confidence level, mean and standard deviation.

Sample data was collected in a study of calcium supplements and their effects on blood pressure. A placebo group and a calcium group began the study with blood pressure measurement. At a 0.05 significance level, test the claim that the 2 sample groups come from populations with the same mean. Placebo mean: 114.6538, standard d

Bumper Installation Standard Deviation

The time taken to install bumpers on cars passing through a particular assembly line is normally distributed with mean time u=2.00 minutes and standard deviation =36 minutes. A sample on n=100 is obtained and a mean bumper installation time X-bar will be calculated. 1. Find the value of standard deviation X bar. Determine th

Statistics Problem

1. Bill has completed a ten question multiple choice test on which he answered seven questions correctly. Each question had one correct answer to be chosen from four alternatives. Bill says that he answered the test by randomly selecting the answers without reading the questions or answers. a. What is the expected number of