The management of White Industries is considering a new method of assembling its golf cart The present method requires 42.3 minutes, on the average to assemble a cart. The mean assembly time for a random sample of 24 carts using the new method was 40.6 minutes and the standard deviation of the sample was 2.7 minutes. Using the
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The manufacturer of the X-15 steel-belted radial truck tire claims that the mean mileage the tire can be driven before the tread wears out is 60,000 miles. The standard deviation of the mileage is 5,000 miles. The Crosset Truck Company bought 48 tires and found that the mean mileage for their trucks is 59,500 miles. Is Crosset's
A physician's health study of the effectiveness of aspirin in the reduction of heart attacks was begun in 1982 and completed in 1987. Of 11,037 male medical doctors in the United States who took one 325 mg buffered aspirin tablet every other day, 104 suffered heart attacks during the five-year period of the study. Of 11,034 male
Experience raising New Jersey Red chickens revealed the mean weight of the chickens at five months is 4.35 pounds. The weights follow the normal distribution. In an effort to increase their weight, a special additive is added to the chicken feed. The subsequent weights of a sample of five-month-old chickens were (in pounds):
The management at Black Angus is considering hiring 8 additional servers. Currently 12 servers are serving 4 tables each per hour. Servers make $11.25 on overtime per hour. Servers are having to work 2 hours of overtime per day 4 days a week. Would hiring 8 additional servers 4 days a week at $7.50 per hour working 6 hour sh
(Q: 12) Suppose you want to develop a model to predict assessed value based on heating area. A sample of 15 single-family houses is selected in a city. The assessed value (in thousands of dollars) and the heating area of the houses (in thousands of square feet) are recorded with the following results: House Assessed Valu
Discuss the null hypothesis. How is it framed? What is the alternate hypothesis? How does it relate to the null hypothesis? Can you have possible outcomes not embraced by the null or alternate hypotheses?
1. The MacBurger restaurant chain claims that the waiting time of customers for service is normally distributed, with a mean of 3 minutes and a standard deviation of 1 minute. The quality-assurance department found in a sample of 50 customers at the Warren Road MacBurger that the mean waiting time was 2.75 minutes. At the 0.05 s
#4.3 Suggest applications of nonparametric methods to solving business related problems. Describe the example. How are you or could you use nonparametric methods to solve business related problems?
Over a period of months an adult male patient has taken eight blood tests for uric acid. The mean concentration iswas x with a line over it =5.35 mg/dl. The distribution of uric acid for the health adult male can be assumed to be normal with the standard deviation of 1.85 mgdl. a. Find a 95% confidence interval for the popula
A study regarding the relationship between age and the amount of pressure sales personnel feel in relation to their jobs revealed the following sample information. At the .01 significance level, is there a relationship between job pressure and age? Degree of Job Pressure Age (years) Low Medium High Less than 25 20 18 22
Records indicate that the mean selling time of farm property is 90 days. Because of drought conditions they believe the mean is now greater. A survey of 100 farms sold recently revealed the mean selling was 94 days with a standard deviation of 22 days. At the .10 significance level, has there been an increase in selling time?
1. The scores on a placement test given to college freshmen for the past five years are approximately normally distributed with a mean µ = 74 and a variance ơ ² = 8. Would you still consider ơ ² = 8 to be a valid value of the variance if a random sample of 20 students who take this placement test this year obtain
Is there sufficient evidence to conclude that there is a significant difference between the percentage of men and the percentage of women who fear flying?
The lives of many people are affected by a fear that prevents them from flying. The Marist Institute for Public Opinion conducted a poll of 1014 adults, 48%of whom were men. The results reported in USA Today showed that 12% of men and 33% of the women fear flying. a) Is there sufficient evidence to conclude that there is a s
Item 1: One- tail (upper): Explain the problem you would test for (make up numbers) and state the hypotheses in both numeric and narrative form. Explain why this would be a upper tailed test. Do no calculations or list any formulas. Item 2: One-tail (lower) Explain the problem you would test for (make up numbers) and state th
The use of cellular phones in automobiles has increased dramatically in the last few years. Of concern to traffic experts, as well as manufacturers of cellular phones, is the effect on accident rates. Is someone who is using a cellular phone more likely to be involved in a traffic accident? What is your conclusion from the follo
For many years, TV executives used the guideline that 30 percent of the audiences were watching each of the prime-time networks and the 10 percent were watching cable stations on a weekday night. A random sample of 500 viewers in the Tampa - St. Petersburg, Florida area last Monday night showed that 165 homes were turned in to t
1. As reported by the College Entrance Examination Board in National College-Bound Senior, the mean verbal score on the Scholastic Assessment Test (SAT) in 1998 was 505 points out of a possible 800. A random sample of 25 verbal scores for last year yielded the following data. 421 571 427 453 390 566 435 460 575 633 4
1. Ten years ago, the mean age of all juveniles held in public custody was 16.0 years, as reported by the U.S. Office of Juvenile Justice and Delinquency Prevention in Children in Custody. The ages of a random sample of juveniles currently being held in public custody are to be used to decide whether this year's mean age of all
Solve using Goal Seek: The Palace Hotel believes it's customers may be waiting too long for room service. The hotel operations manager knows that the time for room service orders is normally distributed and he sampled 10 room service orders during a 3-day period and timed each ( in minutes) as follows: 23 23 15 1
2. Over the past five years, the average amount of sales invoices for Swanson Co. is $120. A random sample of 12 sales invoices from this month averaged $112.85 with a standard deviation of $20.80. Conduct test to find out if average sales invoice this month differs from the historical data. Level of significance a = .05
Statistics Research and Evaluations Questions. 1. A test of hypothesis is always about: a. population parameter b. sample statistic c. a test statistic 2. A critical value is the value a. calculated from sample data b. determined from a table (e.g., normal distribution table or other such table
A recent study of the USA births showed the average birth weight of a male was 8 lbs.; the average weight of a female newborn was 7.4 lbs. I do not believe this to be true; hence, my research, based on a local Hawaiian hospital, showed: the average birth weight of a male was 7.5 lbs with a standard deviation of 2 lbs; the averag
1. A few years ago, a cola manufacturer invited consumers to take a blind taste test. Consumers were asked to determine which of two sodas (brand 1-the manufacturer's own soda, or brand 2 -the competitor's soda) they preferred. The manufacturer was interested in determining what factors played a role in people's taste preferen
Construct a 95% confidence interval estimate of the difference between the percentage of men and the percentage of women who fear flying.
The lives of many people are affected by a fear that prevents them from flying. An institute for public opinion conducted a poll of 1014 adults, 48%of whom were men. The results reported in USAToday showed 12 % of the men and 33% of the women fear flying. 1. Construct a 95% confidence interval estimate of the difference betw
In a randomized controlled trial in Kenya, insecticide treated bednets were tested as a way to reduce malaria. Among 343 infants who used the bednets , 15 developed malaria. Among 294 infants not using bednets, 27 developed malaria. Use a 0.01 significance level to test the claim that the incidence of malaria is lower for infant
The Genetics and IVF Institute conducted a clinical trial of the YSORT method designed to increase the probability of conceiving a boy. 51 babies were born to parents using the YSORT method, and 39 of them were boys. Sample data 0.01 significance level to test the claim that with this method, the probability of a baby being a bo
Question 1: The Survey of Study Habits and Attitudes (SSHA) is a psychological test that measures the motivation, attitude, and study habits of college students. Scores range from 0 to 200 and follow (approximately) a normal distribution with mean 115 and standard deviation 25. You suspect that incoming freshmen have a mean u
Question: To test whether or not there is a difference between the mean grade point average of male math majors and female math majors at a certain university, 2 random samples were gathered. For the 35 males, we find that x1= 3.1 with s1=0.2. For the females, x2=3.2 with s2=0.15. Test at a level of significance of 1%.
Question : Is there a statistically significant difference between the bowling averages of male nurses and those of businessmen, if last year's league play produced the following data: 10 male nurses averaged 180 with s=10 and 15 businessmen averaged 170 with s=10. Use level of significance of 5%.