• Q : Lifetimes of ballpoint pens....
    Basic Statistics :

    A consumer magazine wants to compare the lifetimes of ballpoint pens of three different types. The magazine takes a random sample of pens of each type and the lifetimes are reported in the following

  • Q : Mean elevation drop for ski trails....
    Basic Statistics :

    You just recently read somewhere that the mean elevation drop for ski trails at eastern ski centers is at least 450 feet. You believe that the elevation is lower than 450 feet. Write the null and al

  • Q : Failure to reject the null hypothesis....
    Basic Statistics :

    A skeptical paranormal researcher claims that the porportion of Americans that have seen a UFO, p, is less than 4 in every ten thousand. Assuming that a hypothesis test of the claim has been conduct

  • Q : Nearest integer and then summed....
    Basic Statistics :

    75 numbers are rounded off to the nearest integer and then summed. If the individual round-off error are uniformly distributed over (-.5, .5) what is the probability that the resultant sum differs f

  • Q : Test statistic for a difference of means test....
    Basic Statistics :

    If the test statistic for a difference of means test has a p-value of .03, we could reject the Null Hypothesis at an alpha level of .01.

  • Q : Past experience a professor....
    Basic Statistics :

    Suppose that from the past experience a professor knows that the test score of a student taking his final examination is a random variable with mean 68 and standard deviation 9.5.

  • Q : Degrees of freedom for the test statistic....
    Basic Statistics :

    For a small sample difference of means test where n1 = 20 and n2 = 20, and we can assume the population variances are equal, the degrees of freedom for the test statistic is:

  • Q : Standard error for hypothesis test....
    Basic Statistics :

    Random samples for both airlines after a storm showed that 51 out of 200 flights for Airline A were delayed, while 60 out of 200 of Airline B's flights were delayed. What is the standard error for t

  • Q : Independent random variables....
    Basic Statistics :

    If Jeff and Jack each bowl one game, then assuming that their scores are independent random variables, approximate the probability that the total of their scores is above 285.

  • Q : Mean nose lengths of men and women....
    Basic Statistics :

    A null hypothesis is that the mean nose lengths of men and women are the same. The alternative hypothesis is that men have a longer mean nose length than women. Which of the following is the correct

  • Q : Average life spans between men and women....
    Basic Statistics :

    A researcher wants to prove that there is a difference in the average life spans between men and women in Japan. Let mu1 = average life span of Japanese women and mu2 = average life span of Japanese

  • Q : Small sample difference of means test....
    Basic Statistics :

    For a small sample difference of means test where n1 = 9 and n2 = 11, and we can assume the population variances are equal, the degrees of freedom for the test statistic is:

  • Q : Small sample difference of means test....
    Basic Statistics :

    For a small sample difference of means test where n1 = 12 and n2 = 16, and we can assume the population variances are equal, the degrees of freedom for the test statistic is: A. 27 B. 26 C. 25 D. 28

  • Q : P-value for the test statistic for problem....
    Basic Statistics :

    Random samples for both airlines after a storm showed that 51 out of 200 flights for Airline A were delayed, while 60 out of 200 of Airline B's flights were delayed. The test statistic for this prob

  • Q : Probabilities corresponding....
    Basic Statistics :

    Assume that are searcher randomly selects 14 newborn babies and counts the number of girls selected. The probabilities corresponding to the 14possible values are summarized below.

  • Q : Distribution of grasshoppers....
    Basic Statistics :

    A farmer was interested in determining how many grasshoppers were in his field. He knows that the distribution of grasshoppers may not be normally distributed in his field due to growing conditions.

  • Q : Sample proportion of customers....
    Basic Statistics :

    What is the mean of the sampling distribution of p^ a vegetable garden in the spring? , the sample proportion of customers that plant

  • Q : Studying the effects of fertilizer type....
    Basic Statistics :

    Barbara is a research biologist for Green Carpet Lawns. She is studying the effects of fertilizer type, temperature at time of application, and water treatment after application.

  • Q : Sample of temperatures of initiating certain chemical....
    Basic Statistics :

    A sample of temperatures of initiating a certain chemical reaction yielded a sample average (degrees celcius) of 84.2 and a sample standard deviation of 2.01. What are the sample average and standar

  • Q : Mean of the sampling distribution of p....
    Basic Statistics :

    If p ^ is the sample proportion saying that the food is delicious, what is the mean of the sampling distribution of p ^ ?

  • Q : Average value of equal....
    Basic Statistics :

    John has six bills of paper money in the following denominations: $1, $5, $10, $20, $50, and $100 If he selects 3 bills at a time what is the probability of selecting a group that has an average val

  • Q : Value of the sample test statistic....
    Basic Statistics :

    What is the value of the sample test statistic? (Round your answer to two decimal places.) Find the P-value. (Round your answer to four decimal places.)

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

    Assuming that standard deviation 10.4 seconds, construct and interpret a 90% confidence interval estimate of the population mean of all students. What is the 90% confidence interval for the populati

  • Q : Probability that the trajectory....
    Basic Statistics :

    Compute the probability that the trajectory falls between 0.2 and 0.4.

  • Q : Total width of the two-sided confidence interval on mean....
    Basic Statistics :

    Suppose we wanted the total width of the two-sided confidence interval on mean life to be five hours at 95% confidence. What sample size should be used?

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