Statistics

posted by .

A survey among freshmen at a certain university revealed that the number of hours spent studying the week before final exams was normally distributed with mean 25 and standard deviation 15. A sample of 36 students was selected. What is the probability that the average time spent studying for the sample was between 27.6 and 30 hours studying?

  • Statistics -

    z = (29.6-25)/(15/sqrt(36)

    z = 1.84

    z = (30-25)/(15/sqrt(36)

    z = 2

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Statistics

    A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spent studying per week. Assuming a standard deviation of 6 hours, what is the required sample size if …
  2. Statistics

    A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spent studying per week. Assuming a standard deviation of 3 hours, what is the required sample size if …
  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

    A survey was conducted to measure the number of hours per week adults spend on home computers. In the survey, the number of hours was normally distributed, with a mean of 8 hours and a standard deviation of 1 hour. A survey participant …
  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

    To determine how many hours per week freshmen college students watch television, a random sample of 225 students was selected. It was determined that the students in the sample spent an average of 35 hours watching TV per week. The …
  7. statistics

    A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spent studying per week. Assuming a population standard deviation of 6 hours, what is the required sample …
  8. Math-one more

    The average length of time, per week, that students at a certain university spend on homework is normally distributed with a mean of 24.3 hours and a standard deviation of 1.4 hours. Jane tells her parents she spends more time studying …
  9. Statistics

    A survey among freshman at a certain university revealed that the number of hours spent studying the week before final exams was normally distributed with mean 25 and standard deviation 15. A sample of 36 students was selected. What …
  10. Statistics

    The amount of time the university professors devote to their jobs per week is normally dis- tributed with a mean of 52 hours and a standard deviation of 8 hours. (a) What is the probability that a professor works for more than 56 hours …

More Similar Questions