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    Confidence Interval

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    Minimum Sample Size for Implementing an Honor Code

    Preliminary estimated suggest that about 58% of students at a state university favor implementing an honor code. To obtain a 95% confidence interval for the proportion of all students at the university favoring the honor code, what is the minimum sample size needed if the total width of the confidence interval must be less than

    Confidence Interval

    2. We are interested in purchasing a large collection of Palm M515 PDAs but need to have a general idea of how much we must pay for budgetary purposes. Thus, we will construct a confidence interval on the purchase price and in doing so we will assume that selling prices are close to being normally distributed. A sample of selli

    Confidence Interval Program

    Assume you need to build a confidence interval for a population mean within some given situation. Naturally, you must determine whether you should use either the t-distribution or the z-distribution or possibly even neither based upon the information known/collected in the situation. Thus, based upon the given information for

    Confidence Interval For Effect Of Birth Weight On IQ Score

    Please help with the following. Confidence Interval for Effect of Birth Weight on IQ Score: When investigating a relationship between birth weight and IQ, researchers found that 258 subjects with extremely low birth weights (less than 1000 g) had Wechsler IQ scores at age 8 with a mean of 95.5 and a standard deviation of

    Confidence Intervals for Number of Unpopped Popcorn Kernels

    Biting an unpopped kernel of popcorn hurts! As an experiment, a self-confessed connoisseur of cheap popcorn carefully counted 773 kernels and put them in a popper. After popping, the unpopped kernels were counted. There were 86. (a) Construct a 90 percent confidence interval for the proportion of all kernels that would not p

    97% and 90% Confidence Intervals

    Survey of 60 showed the sample mean is 2.76 and the standard deviation is 0.75. Construct a confidence interval of 90 and 97% for the population mean.

    Confidence interval for apples per tree

    A study of 200 apples trees showed that the average number of apples per tree was 1000. The standard deviation of the population is 200. Which of the following is the 98% confidence interval for the mean number for all apples. a. (967.1, 1032.9) b. (963.8, 1036.2) c. (963.6, 1036.4) d. (972.3, 1027.7)

    The 90% confidence interval of the true proportion

    It was found that in a sample of 90 teenage boys, 70 % of them have received speeding tickets. What is the 90% confidence interval of the true proportion of teenage boys who have received speeding tickets? a. 0.591 < p < 0.812 b. 0.615 < p < 0.805 c. 0.620 < p < 0.780 d. 0.584 < p < 0.830

    Probability , hypothesis testing and confidence interval for a set of problems.

    I would like help with the following exercises for future reference and a better overall understanding. Thanks! 1. The Los Angeles sheriff classifies crimes by age (in years) of the criminal and whether the crime is violent or nonviolent. As shown below, the sheriff reported a total of 150 crimes last year. Age (in years)

    Confidence interval for proportion problem

    Please help with the following problems involving confidence intervals. 1. Find the point estimate p-hat and the margin of error for the confidence interval (0.444, 0.484) 2 With destructive testing, sample items are destroyed in the process of testing them. Crash testing of cars is one very expensive example of destruct

    Confidence interval for mean

    Please see attached. If you can help me with the details of the nine attached questions...with detailed formulas and solutions, I really would appreciate it. 1. Of 139 adults selected randomly from one town, 30 of them smoke. a. Construct a 99% confidence interval for the true percentage of all adults in the town that

    Estimation of the Population Proportion or Mean

    Please see attached worksheet. If you can give me detailed formulas with answers it would be great. 1. The local Tupperware dealers earned these commissions last month: $4377.47 $3183.76 $1970.16 $2270.88 $3860.06 $2508.55 $1569.64 $4205.30 $1663.68 $3960.71 Assuming the population for the amount of commissions ea

    The manager of the Inlet Square Mall, just north of Ft. Meyers

    The manager of the Inlet Square Mall, just north of Ft. Meyers, Florida, wants to estimate the mean amount spent per shopping visit by customers. A sample of 20 customers reveals the following amounts spent: (Data in the excel file). What is the best estimate of the population mean? Determine a 95 percent confidence interval.

    Finding the Confidence Interval

    1. Find the 90 percent confidence interval for the standard deviation of gasoline mileage mpg for these 16 San Francisco commuters driving hybrid gas-electric vehicles. 38.8 48.9 28.5 40.0 38.8 29.2 29.1 38.5 34.4 46.1 51.8 30.7 36.9 25.6 42.7 38.3 2. Biting an un-popped kernel of popcorn hurts! As an experiment, a self

    Confidence interval for mean and proportion..

    Let's assume that the family size factor for the class was collected from randomly selected students taking Elements of Statistics from FHSU?even though we know the data was not randomly collected from such students. a. First, determine from this sample data the proportion (percentage) of students from families of si

    A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. (a) Construct a 90 percent confidence interval for the true mean weight.

    8.46 A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were 3.087, 3.131, 3.241, 3.241, 3.270, 3.353, 3.400, 3.411, 3.437, 3.477 (a) Construct a 90 percent confidence interval for the true mean weight. (b) What sample size would be necessar

    Sample size and confidence interval

    (21) The U.S. Commission of Crime wishes to estimate the fraction of crimes related to firearms in an area with one of the highest crime rates in the country. The commission randomly selects 600 files of recently committed crimes in an area and finds 380 in which a firearm was reportedly used. Construct the 95% confidence interv

    Confidence Interval for the population mean

    The lifetime of a certain brand of electric light bulb is known to have a standard deviation of 49 hours. Suppose that a random sample of 50 bulbs of this brand has a mean lifetime of 491 hours. Find a 95% confidence interval for the true mean lifetime of all light bulbs of this brand. Then complete the table below. Carry yo

    Confidence Interval for Population Mean: T-Distribution

    A random sample of 18 health maintenance organizations(HMOs) was selected. For each HMO, the co-payment(in dollars for a doctor's office visit was recorded. The results are as follows: 6, 12, 7,7,11,9,5,10,12,9,11,12,8,8,5,7,5,8. See the attached file for further details. Under the assumption that co-payment amounts are

    Step by step method for testing the hypothesis under 5 step approach is discussed here. The solution also include the details of sampling distribution of the samples from a normal population.

    1.When you draw a sample from a normal distribution, what can you conclude about the sample distribution? Explain. 2.A mayoral election race is tightly contested. In a random sample of 1,100 likely voters, 572 said that they were planning to vote for the current mayor. Based on this sample, what is your initial hunch? Would y

    Find the sample size needed for a 95% degree of confidence.

    The weekly earnings of middle managers in a large corporation are approximately normally distributed with a standard deviation of 36 dollars. A researcher wishes to estimate the mean weekly earnings. Find the sample size needed if she requires a 95% degree of confidence that the sample mean will not differ from the population by