Share
Explore BrainMass

Dispersion and Spread of Data

Statistics

1. What method of data collection would you use to collect data for a study where a drug was given to 10 patients and a placebo to another group of 10 patients to determine if the drug has an effect on a patient's illness use sampling take a census perform an experiment use a simulatio

Sample Standard Deviation for monthly salaries of sales representatives

Sample standard deviation The monthly salaries (in thousands of dollars) of a sample of 6 sales representatives are as follows: 10, 7, 13, 12, 9, 9 Find the standard deviation of this sample of monthly salaries. Round your answer to at least two decimal places. (If necessary, consult a list of formulas.)

index of the first quartile

Kevin Horn is the national sales manager for National Textbooks, Inc. He has a sale staff of 40 who visit college professors all the over the United States. Each Saturday morning he requires his sales staff to send him a report. This report includes, among other things, the number of professors visited the previous week. List

Standard Deviation of pricing for Mercedes CLK350 vs BMW 3

Suppose Mercedes is concerned that dealer prices of the CLK350 Coupe are not consistent and that even thought the average price is $44,520, actual prices are normally distributed with a standard deviation of $2981. Suppose also that Mercedes believes that at $43,000, the CLK350 coupe is priced out of the BMW 3 series Coupe 335i

Service Levels, Safety Stock, Reorder Point and Service Levels

MassPC Inc. Produces PC Pal model. It takes 1 week to produce a batch. Factory orders are normally distributed with average 400 units per week, and standard deviation of forecast errors is estimated at 125 units. If MassPC wants to provide service level of 80%, how much safety stock should be kept? What is the reorder point? Wha

Continuous Probability Distributions & Sampling Methods; Central Limit Theorem

Ch 07 45.) The goal at U.S. airports handling international flights is to clear these flights within 45 minutes. Let's interpret this to mean that 95% of the flights are cleared in 45 minutes, so 5% of the flights take longer to clear. Let's also assume that the distribution is approximately normal. a.) If the standard

Finding Mean and Standard Deviation: Winery Example

You are in charge of storage at a winery. A 60 gallon barrel of wine weighs on average 120 lbs with a standard deviation of 6 lbs. One gallon of wine weighs about 8 lbs with a standard deviation of .40 lbs. You store barrels on shelves on your property. a. What is the expected mean and standard deviation of the weight

Statistics: US Army weapons choice

See attached file. The head of research and development for the US Army must select from the accompanying list one of the antitank weapons for procurement. The listed results are based on the distance away from intended target that 100 tests rounds fell. Which system would the army select and why? Provide a detailed answer. T

Excel functions for use in statistics

See attached files. The questions and solutions are attached for a group of problems, but I don't know how to work them in Excel. All references in the questions are also attached. Please assist with the Excel commands.

Statistics

1.                   The number of hours needed by students in a science class to complete a research project was recorded with the following results: hours Number of Students(freq) 0 - 14 2 15 - 29 4 30 - 44 10 45 - 59 16 60 - 74 6 7

Step by step instructions

I need help understanding how to calculate the problems below. I would like to see the steps taken to find the solution (not just formulas excel provides). Thanks 1. At the time she was hired as a server at the Grumney Family restaurant, Beth Brigden was told, "You can average more than $20 a day in tips." Over the fi

Payne (2001) Gave Participants a Computerized Task - Mean and Standard Deviation

Payne (2001) gave participants a computerized task in which they first see a face and then a picture of either a gun or a tool. The task was to press one button if it was a tool and a different one if it was a gun. Unknown to the participants while they were doing the study, the faces served as a "prime" (something that starts y

Distribution of Weights for Samples

I simply need help with setting up the formula or an example of how to complete the problem on my own. I have been reading the topics but nothing explained what formula to use to get the answer so can someone please show me the steps so I can compute it myself. 1.) The distribution of weights for a sample of 1,400 cargo co

Standard Deviation for Psychology Exam

For a particular sample of 50 scores on a psychology exam, the following results were obtained. First quartile = 67 Third quartile = 91 Standard deviation = 9 Range = 48 Mean = 75 Median = 80 Mode = 81 Midrange = 74 a)What score was earned by more students than any other score? Why? b)How many students scored b

Summation Notation, Percentile and Proportion

Please show your work. I am having trouble working out the problems. I would like as detailed an explaination for the answers as you can give. 1. A teacher gives a 20-point quiz to 10 students. The scores are listed below. What percentile corresponds to the score of 12? 20 8 10 7 15 16 12 19 14 9 A. 13 B. 40 C.

Mean, variance and standard deviation

The sales records for a real estate company are given. From the sample data, the following frequency distribution has been developed. Sale Price (1000's) Number of Houses Sold (frequency) 20-39 1 40-59 2 60-79 4 80-99

Statistics - Highest Relative Score

Comparing Scores. Three students take equivalent tests of sense of humor and, after the laughter dies down, their scores are calculated. Which is the highest relative score? A. A score of 144 on a test with a mean of 128 and a standard deviation of 34. B. A score of 90 on a test with a mean of 86 and a standard deviation of

Standard deviation

An employer wants to set a time limit so that 90% of the employees will finish a job on time. Past history has shown that the time required to do the job is normally distributed and has a mean time of 32 minutes with a standard deviation of 6 minutes. How much time should the employer allow employees to finish the job? (Round

Average and Standard Deviation of Revenue

The revenues collected at a web site are about to change because the sales tax rate is going up from 8% to 9%. By what percent do revenues increase? Previously, the average revenue was $76.35 and the standard deviation was $29.06. Assuming the same mix of orders at the same prices, what do you anticipate for the new average and

Basic Statistics and Bar Graphs

1. Find the first and third quartiles, Q1 and Q3, of the following set of numbers. 0.16, 0.08, 0.27, 0.20, 0.22, 0.32, 0.25, 0.18, 0.28, 0.27 a. 0.16; 0.28 b. 0.18; 0.27 c. 0.16; 0.27 d. 0.18; 0.28 2. Continent or Region Land Area (1,000 mi2) % of Earth Population 1900 Population 1950 Population 2000 North Am

Standard Deviation

Investigating distribution & standard deviation question Q9) b. A quality control engineer redesigns repair procedures so that the standard deviation of the repair times is reduced. Does this imply that the repairs are being done in less time? Why or why not?

Investigating distribution & standard deviation questions

A. When investigating the distribution of a data set, which is more effective: a frequency distribution or a histogram? Why? b. A quality control engineer redesigns repair procedures so that the standard deviation of the repair times is reduced. Does this imply that the repairs are being done in less time? Why or why not?

Development of a Test to Measure Depression

Dr. Zak Case Study INSTRUCTIONS Read the following case study. Then, use the information in the case study to answer the accompanying follow-up questions. Although questions 1-2 have short answers, you should prepare a 150 to 200-word response to each of the remaining questions. CASE STUDY Dr. Zak developed a test to measure

Standard Deviation

The Rocky Mountain district sales manager of JCM, Inc., a college book publishing company, claims that each of his sales representatives makes 40 calls on professors per week. Several reps said that this estimate is too low. To research the claim, a random sample of 28 reps revealed that the mean number of calls made last week

15 Problems : Five-Number Summary, GCF, Factorization, Perimeter and Area

4. Jamal is fencing a rectangular field that measures 40 ft by 15 ft. How much fencing should he buy? 7. Find the prime factorization of the number 360. 8. Find the greatest common factor of 16, 12, and 100. 13. Find the least common multiple of 15 and 21. 18. Jacque earns $9.60 per hour (h). For overtime (each h

Normal Distribution: First Mortgage

The average conventional first mortgage for new single-family homes was $294,000. Assuming a normal distribution and a standard deviation of o = $30,000, what proportion of the mortgages were: a. more than $294,000? b. between $234,000 and $354,000? c. between $264,000 and $342,000? d. more than $204,000?

Time Measurement and Histogram Construction

1. A psychologist is studying the length of time it takes mice to go through a maze and reach a reward at the end. Time is measured to the nearest tenth of a second with the results given in the table below. Time Frequency 2.0 up to 3.0 3 3.0 up to 4.0 7 4.0 up to 5.0 15 5.0 up to 6.0 29 6.0 up to 7.0 81 7.0 up to 8.0