• Q : Probability of getting less....
    Basic Statistics :

    A mail order company has an 8% success rate. If it mails advertisements to 600 people, find the probability of getting less than 40 sales?

  • Q : Confidence interval for the mean....
    Basic Statistics :

    A normally distributed random variable Y has std dev. = 800. A random sample of 100 observations was taken from Y, and the sample average observed was 1400. Find the right endpoint of the symmetric

  • Q : Standard deviation of the population....
    Basic Statistics :

    Construct a 96% confidence interval for the true mean breaking strength of a certain type of 10 ft. long cables. Assume that there are 100 such cables with mean X ? = 457 lbs while the standard devi

  • Q : Dimension of a certain part after grinding....
    Basic Statistics :

    In a grinding operation, there is an upper specification of 3.150 in. on a dimension of a certain part after grinding. Suppose that the standard deviation of this normally distributed dimension is ?

  • Q : Determine the average number of ounces....
    Basic Statistics :

    Now suppose the standard deviation is 1.5 ounces. Determine the average number of ounces the machine should dispense so that no more than 2.5% of the bottles contain less than 19.5 ounces.

  • Q : Average tax refund....
    Basic Statistics :

    According to the IRS, the average tax refund for the 70 million personal income tax returns in 1998 was $800. Assuming a standard deviation of $220, find the probability that for a random sample of

  • Q : Mean and sample standard deviation....
    Basic Statistics :

    By showing work with mean and sample standard deviation, verify that x bar is approximately equal to 74.2 cm and s is about 18.3 cm.

  • Q : Hypothesis-critical value-degrees of freedom....
    Basic Statistics :

    Find solutions to the following problem. Be sure to include all relevant information, including hypothesis, critical value, degrees of freedom, and a statement about significance.  

  • Q : Determining the distribution of weights....
    Basic Statistics :

    The distribution of weights can be approximately normal with mean 90 grams and a standard deviation of 1 gram. What percentage of items will either weigh less than 87 grams or more than 93 grams?

  • Q : Grams and a standard deviation....
    Basic Statistics :

    The distribution of weights can be approximately normal with mean 90 grams and a standard deviation of 1 gram. What percentage of items will either weigh less than 87 grams or more than 93 grams?

  • Q : Results of a regression analysis....
    Basic Statistics :

    A large national bank charges local companies for using their services. A bank official reported the results of a regression analysis designed to predict the bank's charges (y), measured in dollars

  • Q : Sample percentage of those equating success....
    Basic Statistics :

    How large of a sample is needed if we wish to be 95% confident that the sample percentage of those equating success with personal satisfaction is within 1% of the poulation percentage?

  • Q : Technology services department at lahey electronics....
    Basic Statistics :

    An internal study by the Technology Services department at Lahey Electronics revealed company employees receive an average of 5 emails per hour. Assume the arrival of these emails is approximated by

  • Q : Confidence interval for the mean life of a light bulb....
    Basic Statistics :

    Form a 90% confidence interval for the mean life of a light bulb made by Acme Corporation. (Round the answers to three decimal places.)

  • Q : Confidence interval for the mean depth....
    Basic Statistics :

    Compute a 95% confidence interval for the mean depth 'mhu' at which archaeologicial artifacts from the Wind Mountain excavation site can be found.

  • Q : Anxiety and exam score....
    Basic Statistics :

    Given the correlation value between anxiety and exam score, could you assume that heightened anxiety is causing, at least to some degree, lower exam scores?

  • Q : Margin of error and the confidence interval for the mean....
    Basic Statistics :

    Starting salaries of 70 college graduates who have taken a statistic course have a mean of $42,823 and a standard deviation of $10,934. Using 99% confidence, find the margin of error and the confide

  • Q : Confidence interval for the mean gross earnings....
    Basic Statistics :

    For 30 randomly selected Rolling Stones concerts, the mean gross earnings is 2.9 million dollars. Assuming a population standard deviation gross earnings of 0.48 million dollars, obtain a 99% confi

  • Q : Equation of the least squares line....
    Basic Statistics :

    Calculate the equation of the least squares line that you would use to predict stride rate from speed. (Round all numerical values to four decimal places.)

  • Q : Construct an appropriate markov chain....
    Basic Statistics :

    However, if she gives a medium or easy test, there is a 0.5 probability that her next test will be of the same difficulty and a 0.25 probability for each of the other two levels of difficulty. Const

  • Q : Number of fish caught....
    Basic Statistics :

    In "Boston Record Game Fishes", it is stated that in the Cozumel region, approximately 40% of strikes (while trolling) result in a catch. Suppose that on a given day a fleet of fishing boats got a t

  • Q : Goodness-of-fit test for equal expected frequencies....
    Basic Statistics :

    What is the difference between the goodness-of-fit test for equal expected frequencies and unequal expected frequencies? Example

  • Q : Leaders for making deep budget cuts....
    Basic Statistics :

    Europeans are increasingly upset at their leaders for making deep budget cuts to many social programs that are becoming too expensive to sustain. For instance, the popularity of then President Nicol

  • Q : Compare the quality of cell phones....
    Basic Statistics :

    An electronics company wants to compare the quality of their cell phones to the cell phones from three competitors. They sample 10 phones from each company and count the number of defects for each p

  • Q : Proportion of the workforce....
    Basic Statistics :

    You plan to conduct a survey to find what proportion of the workforce has two or more jobs. You decide on the 99% confidence level and state that the estimated proportion must be within 2% of the po

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