statistics

posted by .

School 1 Statistics: Average truancy per student is 8 days per semester with a standard deviation 2.2 and a population of 250 students.
a. What percent of the population is truant more than 9 days?
b. What percent of the population is truant less than 3 days?
c. What percent of the population is truant between 5 and 10 days?
d. What percent of the population is truant between 8.5 and 10 days?
e. What raw score would produce a truancy percent of the top 15% of the students who missed the least amount of school?

  • statistics -

    Z = (score-mean)/SD

    Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the various Z scores.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math

    According to a student project for statistics 250, the amount of money spent on texts per semester by the population of students at a small liberal arts college is normally distributed with a mean of $426 and a standard deviation of …
  2. Math please help!

    According to a student project for statistics 250, the amount of money spent on texts per semester by the population of students at a small liberal arts college is normally distributed with a mean of $426 and a standard deviation of …
  3. statistics

    a random sample of 100 college students is taken from the student body of a large university. assume that a population mean of 20 hours and a population standard deviation of 15 hours describes the weekly study estimates for the entire …
  4. math

    Average truancy per student is 8 days per semester with a standard deviation 2.2 and a population of 250 students. a. What percent of the population is truant more than 9 days?
  5. 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 …
  6. statistics

    A random sample of 31 people employed by the Florida state authority established they earned an average wage (including benefits) of $56 per hour. The sample standard deviation was $6.35 per hour. (a)What is your best estimate of the …
  7. Statistics

    A study is being planned to estimate the mean number of semester hours taken by students at a college. The population standard deviation is assumed to be o=4.7 hours. How many students should be included in the sample to be 99% confident …
  8. math

    You manage inventory for your company and use a continuous review inventory system to control reordering items for stock. Your company is open for business 310 days per year. One of your most important items experiences demand of 24 …
  9. 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 …
  10. Stats

    At a certain university, the average cost of books was $370 per student last semester and the population standard deviation was $80. This semester a sample of 45 students revealed an average cost of books of $390 per student. The Dean …

More Similar Questions