Please see attached file for full problem. Hypothesis test for the difference of population means: Z test According to the historical data, the life expectancy in the United States is equal to the life expectancy in Japan. A new study has been made to see whether this has changed.
Exercise 8.5 Find a confidence interval for u assuming that each sample is from a normal population. a. x = 14, sigma = 4, n = 5, 90 percent confidence b. x = 37, sigma = 15, 99 percent confidence c. x = 121, sigma = 15, 95 percent confidence Exercise 9.19 Calculate the test statistic and p-value for each sample.
An insurance company states that 90% of its claims are settled within 5 weeks. A consumer group selected a random sample of 100 of the company's claims and found 75 of the claims were settled within 5 weeks. Is there enough evidence to support the consumer group's claim that fewer than 90% of the claims were settled within 5 we
A certain test is designed to measure the satisfaction of an individual with his/her relationship. Suppose that the scores on this test are approximately normally distributed with a mean of 55 and a standard deviation of 8. An individual with a score of 40 or less is considered dissatisfied with his/her relationship. According t
A manufacturer claims that the mean lifetime, , of its light bulbs is 49 months. The standard deviation of these lifetimes is 9 months. Seventy bulbs are selected at random, and their mean lifetime is found to be 46 months. Can we conclude, at the .01 level of significance, that the mean lifetime of light bulbs made by this manu
WHAT IS WRONG and WHY? 1. A statistician is going to survey a sample of 50 people. He prepared a list of 50 random phone numbers generated by a computer. Next morning he came to work at 8:00 and began to make calls. By 11:00 a.m., his survey was done. 2. The United Nation declared that the world's six-billionth inhabit
Please see the attached file.
Question: The height in inches of girls on a high school girls basketball team are as follows: 60.0 61.0 62.5 64.0 66.5 Identify the z score used in a quantile plot for the player with a height of 66.5 inches. z=
Briefly explain what percentages of the cases in the normal curve you can obtain by using a z-score of 2.58 as a cutoff point. Specifically: A. Discuss the percentages in the middle area (near the mean). B. Discuss the percentages in the tails.
A Special Case of z-scores You learned that 47.50% of the cases lie between the mean and a z-score of +1.96. For each answer, draw a normal curve, and shade in your answer. A. What percentage of the cases lies between a z-score of -1.96 and 1.96? B. What percentage of the area in normal curve lies in the tails after you
You know that 34.13% of the cases lie between the mean and a z-scores of +1.00. For each answer, draw a normal curve, and shade in your answer. A. What percentage liew between the mean and a z-score +1.00? B. What percentage lies in the tail above a z-score of +1.00 C. What percentage of the cases lies between a z- scores
What is the z value to the right of the mean such that 85% of the total area lies to the left?
A five-year old study claims that selling prices of new homes / condominiums in the New York area have a normal distribution with mean = $180,000 and standard deviation = $40,000. a. Assuming that the results of the study are still valid, what is the probability that a randomly selected new house in the New York area will cos
Perform hypothesis testing on one variable's data. (Choose either the intrinsic or extrinsic column.) Perform a t-test by formulating a null and an alternative statement, choosing an acceptable significance value, selecting the test statistic and determining its value from the sample data, comparing the observed value to the cri
Question 2. The number of patrons attending the local sports bar each evening during footballs season follows the normal distribution. The mean number of patrons per evening is 240 and the standard deviation is 35. a) What percent of the evenings will have between 185 and 240 patrons? b) What percent of the evening wi
Find the standard deviation for the given data. Round your answer to one more decimal place than the original data. 54) 15, 42, 53, 7, 9, 12, 14, 28, 47 54) ______ A) 15.8 B) 29.1 C) 17.8 D) 16.6 Use the empirical rule to solve the problem. 55) The systo
The standard normal table shows an area value of 0.1 for a z-score of 0.25 and an area value of 0.35 for a z-score of 1.04. What percentage of the observations of a random variable that is normally distributed will fall between 0.25 standard deviations below the mean and 1.04 standard deviations above the mean?
10. and 11. For a population with mean of 14 and standard deviation of 2.5 ... How many standard deviations is 16.5 from the mean? What number is -3.1 standard deviations from the mean? 12. Find the cumulative area under a standard normal curve that corresponds to a z-score of 2.25.
The election is one week away. You think you have the election sewn up, but the seem appears to be unraveling. You run a poll, draw a random sample of 500 adults. 54% say they will vote for your candidate. Will your candidate win? Prove it.
1. The accounting department at Weston Materials, Inc. a national manufacturer of unattached garages, reports that it takes two construction workers a mean of 32 hours and a standard deviation of 2 hours to erect the Red Barn model. Assume the assembly times follow the normal distribution. a) Determine the z values for 29 and
A nationwide sample of influential Republicans and Democrats was asked as a part of a comprehensive survey whether they favored lowering environmental standards so that high-sulfer coal could be burned in coal-fired power plants. The results were: Republicans Democrats Number Samples 1,000 800 Number in Favor 200 16
Past data indicates an 80% (0.8) success rate in treating a certain medical problem. A new treatment is used on 100 patients in a clinical trial. It is successful in 87% (0.87) of the cases. What is the value of the z-score that can be used to test the null hypothesis that the success rate is 80%?
If you just want to make a prediction about the proportion of nurses (and not do a z-test), you'll have to find more data points. You could sample several different employers, or look at different departments within the place where you work. In either case, you'd have many different proportions in your sample. You would calculat
Conduct pilot studies about a mean and a proportion aspect of the place where you work. Find sample mean/proportion and use these results to make estimates of the corresponding population parameters. See attached file for full problem description. The population where I work is 5000 employees. I was going to do a proportion b
An entrepreneur is considering the purchase of a coin operated laundry. The present owner claims that over the past 5 years, the average daily revenue was $675 with a standard deviation of $75. A sample of 30 days reveals a daily average revenue of $625. If you were to test the null hypothesis that the daily average revenue was
Let x be a random variable that represents the length of time it takes a student to write a term paper for Dr. Adam's Sociology class. After interviewing many students, it was found that x has an approximately normal distribution with mean μ = 6.8 hours and standard deviation σ = 2.1 hours. Convert each of the following x
5. Consider an infinite population with a normal shape and a mean of 300 and standard deviation of 30. a. Compute the z-scores for the following values of X and locate each on the graph. X Z-score 200 360 220 270 300 b. According to the Empirical rule what percent of the data should be between 270 and 330? Betw
Here is a sample of 106 body temperatures (attached file) with a mean of 98.20 F. Assume that σ is known to be 0.62 F. Consider a hypothesis test uses a 0.05 significance level to test the claim that the mean body temperatures of the population is less than 98.6F. a. What is the test statistic? b. What is the critical
A. A normal distribution has Mu = 40 and standard deviation = 8 Describe the distribution of sample means based on samples of n = 16 selected from this population. Of all the possible samples of n = 16, what proportion will have sample means greater than 42? Of all the possible samples of n = 16, what proportion will have sa
1.) A normal distribution has a mean=60 and a standard deviation=6. Find the following probabilities: p(X>56) p(X<70) p(52<X<68) p(61<X<75) 2.) A normal distribution has a mean=35 and standard deviation=5. Find the scores associated with the following regions: a.) the score needed to be in the 43rd percentile. b.) T