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Dispersion and Spread of Data


SEE ECCO INFO ATTACHED The quality manager at Ecco Company, a maker of back-up alarms for use on industrial vehciles such as forklifts, is interested in estimating the mean dollar volume for warranty claims for products made in Boise on the day shift. He has taken a pilot sample. See info attached. a. Assuming that the

Random Sampling and Error

6.1 Consider the following data to be a population of N=20 values ______________________________________________________________ 5 3 2 6 6 7 3 3 6 7 7 9 7 5 3 12 6 10 7 2 ___________________________

Confidence Interval and Random Sample

1. A confidence interval for a population mean has a margin of error of 10.7. What is the length of the confidence interval? 2. A random sample of size 17 is taken from a population. A normal probability plot of the sample data is found to be very close to linear. The population standard deviation is unknown. The appropriate m

Probability and Standard Deviation Questions

1. The time that the customers at the "self serve" check out stations at the Mejers store spend checking out follows a uniform distribution between 0 and 3 minutes. a. Determine the height and draw this uniform distribution. b. How long does the typical customer wait to check out? c. Determine the standard deviation of the

Probability & Standard Deviation

14. A file cabinet manufacturer estimates that 5% of its file cabinets will have drawers that close improperly. Assume a production run of 120 cabinets is completed. a. What is the mean and standard deviation of this distribution? b. What is the probability that 7 or more are defective? c. What is the probability that exactly

Standard Deviation

The true length of boards cut at a mill with a listed length of 10 feet is normally distributed with a mean of 123 inches and a standard deviation of 1 inch. What proportion of the boards will be over 125 inches in length?

What do you think the market shares will be next month?

Over any given month, Dress-Rite loses 10% of its customers to Fashion, Inc., and 20% of its market to Luxury Living. But Fashion, Inc., loses 5% of its market to Dress-Rite and 10% of its market to Luxury Living each month; and Luxury Living loses 5% of its market to Fashion, Inc., and 5% of its market to Dress-Rite. At the p

Probability calculations based on normal probability

1. Suppose that the random variable x is normally distributed with mean = 1,000 and standard deviation = 100. Sketch and find each of the following probabilities: a. P(1,000<_x<_1,200) e. P(x<_700) b. P(x>1,257) f. P(812<_x<_913) c. P(x<1,035) g. P(x>891) d. P(85

Stem and leaf, means, standard deviations, t-testin

In order to study the return on assets in the bio-techinlohy industry, a sample of cmpanies was selected randomly. Their rate of returns (X in percent) are shown in the attached document. A) Prepare stem and leaf display B) Calculate the mean rate of return and standard deviation of the rates of return C) If the reat of re

Mean and Standard Deviations

Advertising expenses are significant component of the cost of goods sold. Listed below is a frequency distribution showing the advertising expenditures for 60 manufacturing companies located in the Southwest. Estimate the mean and the standard deviation of advertising expense. See attached file for chart.

Quartiles, deciles, and various percentiles.

The Thomas Supply Company, Inc. is a distributor of small electrical motors. As with any business, the length of time customers take to pay their invoices is important. Listed below, arranged from smallest to largest, is the time, in days, for a sample of The Thomas Supply Company, Inc. invoices. a. Determine the first and t

Given the data (listed in problem), find the 3rd quartile (Q3)

The following data represents the processing times required to pack 20 randomly selected computer hardware orders for mailing: 5.62 16.25 11.46 8.45 5.41 11.62 7.5 4.42 7.58 7.54 5.29 10.92 21.62 8.58 11.42 7.29 7.96 10.5 9.29 8.92 What is the third quartile? A. 10.92 B. 11.05 C. 11.42 D. 11

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

Standard Deviation

A young advertising executive for Orlando Dining was not satisfied when her junior analyst gave her the point estimate that the average number of magazines sold per month was 11,500. She wanted to know more than just a point estimate. What do you think her next statistical request was of the junior analyst?

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?

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 sh

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