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Find the least-squares equation to predict sales from number of clients. Can the least squares equation be used to predict sales?
He collects information from 82 walk-in customers and calculates that their average waiting times that is 21 minutes with a standard deviation of 4 minutes. a)Determine the degrees of freedom to be
What is the estimated index of satisfaction for a person who first married at 18, has an annual income of $26,500, has three children living, has assets of $156,000, has an index of health status of
A market research is available for $10,000. Using a decison tree analysis, it is found that the expecyed monetary value with no survey is $62,000. If the expected value of sample information is -$7,
Define the flow time to be the total time it takes a product to go through the assembly line from start to finish. What is the mean and standard deviation of the flow time? What is the probability t
The State Transportation Department is interested in estimating the proportion of vehicle owners that are operating vehicles without the required liability insurance. If they wish to estimate the po
A manufacturer of headache medicine claims it is 70% effective within a few minutes. That is, out of every 100 users, 70 get relief quickly. A group of 12 patients are given the medicine. If the cl
A sample of 18 homes, also sold within the last year,that were one to three blocks from the ocean revealed that the standard deviation was $21,330. At the .01 signficance level, can we conclude that
Given that the safety conditions at the plant remain the same next year, what is the probability that the number of serious injuries will be less than 2?
A sample of 8 appendectomies using the old method had a mean of 38 minutes with a variance of 36 minutes, while a sample of 10 appendectomies using the experimental method had a mean of 29 minutes
If a correlation coefficient of r = 0.642 was found between two variables in a sample of paired data that were measured in feet, the value of r would change by a factor of twelve if the data were co
Assume that the bulb life is normally distributed. At the 10% significance level, do the data provide evidence that the mean life for the company's light bulbs differs from the advertised mean?
The bottled water increases during a hot spell of weather. How could you apply statistical critical thinking in this situation?
The distribution of the battery lives closely follows the normal probability distribution with a standard deviation of 5.5 hours. As a part of their testing program Sony tests samples of 25 batteri
Data from this study came from the "National Women's Study-Replication." The sample of 3,001 women was formed from two U.S. population samples. What is your analysis of this approach?
A watch manufacturer creates watch springs whose properties must be consistent. In particular, the standard deviation in their weights must be no greater than 2.0 grams. Fifteen watch springs are se
Cumulative frequency distribution, histogram, ogive and stem and leaf display. Calculate appropriate summary statistics. Incorporate these graphs and statistics into a well written summary
About 13% of the population is hopelessly romantic. If two people are randomly selected, what is the probablity both are hopelessly romantic?
The cutoff t needed is -1.833. The standard deviation of the distribution of means of change scores is 2.0 and the mean change score for the sample studied is an increase of 5.2. What is the t score
Assume the probability that a person has the desease is 0.08 for all people, independently of each other. Compute the total expected number of tests necessary.
According to a study 7% of the population has lung disease. Of those having lung disease, 90% are smokers. Of those not having lung disease, 25.3% are smokers. Determine the probability that a rando
Find the average caller "on hold" time if the company maintains that no more than 9% of callers wait more than 6.6 minutes.
A researcher conducts a t test for dependent means with 10 subjects. If the estimated population variance of the change scores is 20, what would the variance of the distribution of the means of chan
A machine that manufactures automobile parts is estimated to produce defective parts 6 % of the time. If this estimate is correct, and 10 parts produced by this machine are randomly selected, what i
A scientist wishes to find the 90% confidence interval for the mean number of peaches per tree. How many trees does she need to sample to be accurate within 10 peaches per tree?