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Dispersion and Spread of Data

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

Employees Absent on a Chosen Work Day

From historical records, a personnel manager of a plant has determined the distribution below for random variable X, the number of employees absent on a randomly chosen work day. A) What is the probability that two or fewer employees are absent? B) What is the expected number of employees absent? C) What is the variance of t

Statisitics: Mean, Median, Mode and Pie Charts

Please see the attached file for the fully formatted problems. 1. Find the mean of the following set of numbers. 13, 15, 18, 18, 18, 19, 22, 26, 28, 33 2. Find the median of the following set of numbers. 24, 26, 31, 33, 35, 36 3. Find the mode of the following set of numbers. 22, 55, 43, 26, 33, 36, 43, 2

Age Distribution of Prehistoric Native Americans

This is a 3 step problem requested as an example however we have not gone over how to do this yet, I need help with understanding these steps. I have a chart with the greek letters and numbers but am not sure how to put this in order. It is requested to answer and show work so whatever help you may offer will help me better unde

Statistics - Siting Distance ...

A common design requirement is that an item (such as an aircraft or theater seat) must fit the range of people who fall between the 5th percentile for women and the 95th percentile for men. If this requirement is adopted, what is the minimum sitting distance and what is the maximum sitting distance? For the siting distance, us

Step-by-step Answer to Statistics Comparing Scores

Comparing Scores. 3 students take equivalent test of a sense of humor and, after the laughter dies down, their scores are calculated which is the highest relative score? 1. A score of 144 on a test with a mean of 128 and a standard deviation of 34? 2. A score of 90 on a test with a mean of 86 and a standard deviation of

Statistics, Averages and Variations

Record of heights in inches: (the 4 is correct) 65,72,68,64,60,55,73,71,52,63,61,74,69,67,74,50,4,75,67,62,66,80,64,65. Lower limits Q1 - 1.5 X ( IQR) Upper limits Q3 + 1.5 X (IQR) A) Make a ox and whisker plot of the data B) Find the value of the interquartile range (IQR) C) Multiply the IQR by 1.5 and find the lower an

Predicting Mean and Standard Deviation

If the sampled population has a mean of 48 and a standard deviation of 16, then the mean and the standard deviation for the sampling distribution of x -bar for n = 16 is?

Probability: Amount of Time Professors Devote to Their Jobs

The amount of time the university professors devote to their jobs per week is normally distributed with a mean of 52 hours and a standard deviation of 6 hours. a) What is the probability that a professor works for more than 60 hours per week? b) Find the probability that the mean amount of work per week for three randomly se

Standard Error of the Sampling Distribution of the Mean

A) Suppose that the standard deviation of a population with N= 10,000 members is 500. Determine the standard error of the sampling distribution of the mean when the sample size is 1,000. B) Repeat part A when n=500 C) Repeat part A when n=100

Factors that Influence the Value Obtained for a T-Statistic

Several factors influence the value obtained for a t-statistic. Some factors affect the numerator of the t statistic and others influence the size of the estimated standard error in the denominators. For each one of the following, indicate whether the factor influences the numerator or denominator of the t statistic and determin

Basic statistics: mean, variance and standard deviation

1. Plywood, Inc. reported these returns on stockholder equity for the past 5 years: 4.3, 4.9, 7.2, 6.7, and 11.6. Consider these as population values. a. Compute the range, the arithmetic mean, the variance, and the standard deviation. 2. The annual incomes of the five vice presidents of TMV Industries are: $125,000; $128,0

Statistics: Quantative Data Analysis

A woman sells an average of 300 books per month, with a standard deviation of 50. Over the next ten years, how many months will she sell more than 375 books? (round to the nearest month, if necessary)

Comparing Standard Deviations At the .01 Significance Level

A real estate agent in the coastal area of the Carolinas wants to compare the variation in the selling price of homes on the oceanfront with those one to three blocks from the ocean. A sample of 21 oceanfront homes sold within the last year revealed the standard deviation of the selling prices was $45,600. A sample of 18 homes,

Expected Value and Standard Error

For a sample selected from a population with a mean of u=50 and a standard deviation of o=10: what is the expected value of M and the Standard error of M for a sample of n=4 scores?

Prime numbers, fractions, etc

(See attachment for details) 11 A baseball player scored a total of 27 runs in the first 20 games of the season. If he continues at the same pace, how many runs should he score in the 80-game season? Show Work Below 12 Estimate the result in the following division problem. (Remember to round divisors to the neares

Describing and Summarisng Data Sets

Find the median of each set of numbers. 1. 26, 30, 38, 67, 59, 21, 17, 85, 22, 22 Give the Five numbers summary of each set of numbers. 2. 7, 7, 5, 4, 1, 9, 8, 8, 8, 5, 2 One measure used to describe a data set is the range. The range of a data set is given by the difference between the max and the min of the set. Th


Given the following data set, find the value that corresponds to the 75th percentile. 10, 44, 15, 23, 14, 18, 72, 56

the impact of an outlier on the mean

Given a sample of 50 IQ scores ranging from 80 to 145, if the 145 were accidentally typed in error as a 415, what would be the impact on the following statistics? (Answer with increase, decrease or remains the same.) The mean. The median. The standard deviation. The range.