statistics

posted by .

2. The director of admissions at a large university advises students that the cost of textbooks will average more than $300 for a typical semester. A random sample of 80 students enrolled in the university shows a sample mean cost of $315.40 and a sample standard deviation of $43.20. Use a 5% level of significance to test the director's claim.

  • statistics -

    I am wondering what the standard deviation is: is that the standard deviation on the textbook cost, or the standard deviation on the 80 students individual average?

  • statistics -

    standard deviation on the 80 students individual average

  • statistics -

    Determine your null and alternate hypothesis.

    Use the z-test formula to find the test statistic:
    z = (sample mean - population mean)/(standard deviation divided by the square root of the sample size)
    z = (315.40 - 300)/(43.20/√80)

    I'll let you finish the calculation.

    Once you have the z-value from the above calculation, compare it to the critical value at .05 level of significance for a one-tailed test using a z-table. If the test value exceeds the critical value from the table, reject the null. If it does not exceed the critical value, do not reject the null. You can then draw your conclusions.

    Hope this helps get you started.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. business statistics

    The director of admissions at a large university says that 15% of high school juniors to whom she sends university literature eventually apply for admission. In a sample 0f 300 persons to whom materials were sent, 30 students applied …
  2. statistics

    In a study of the effect of college student employment on academic performance, the following summary statistics for GPA were reported for a sample of students who worked and for a sample who did not work.( university of central florida …
  3. Statistics

    28. A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spend studying per week. Based on a simple random sample, they surveyed 144 students. The statistics …
  4. statistics

    1. The on-campus housing costs for a semester at a state university are Normally distributed with a mean of $1553 and a standard deviation of $329. (a) What is the distribution of the mean on-campus housing cost for a semester at this …
  5. statistics

    the dean of admissions in a large university has determined that the scores of the freshman class in a mathematics test are normally distributed with a mean of 86 and a standard deviation of 11. A sample of 50 students is selected …
  6. statistics

    The GPAs of all students enrolled at a large university have an approximately normal distribution with a mean of 3.02 and a standard deviation of .29. Find the probability that the mean GPA of a random sample of 20 students selected …
  7. statistics

    1. A simple random sample of 400 students is taken at a large university. The average height of the sampled students is 68 inches and the SD is 2 inches. The distribution of heights in the sample follows the normal curve very closely. …
  8. statistics

    1. A simple random sample of 400 students is taken at a large university. The average height of the sampled students is 68 inches and the SD is 2 inches. The distribution of heights in the sample follows the normal curve very closely. …
  9. statistics

    Describe whether the following study would most likely be “observational” or “experimental”, and why it would be so. A survey examines the preferences for laundry detergent. ***The admissions office wants to estimate the cost …
  10. statistics

    The Dean of a university claims that no more than 10% of the students drop out of university. She chooses a random sample of 500 students and decides that she will accept the claim only if no more than 25 of the 500 students drop out …

More Similar Questions