This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: Scores on a recent national statistics exam were normally distributed with a mean of 80 and a ... (Read 66 times)

penza

  • Hero Member
  • *****
  • Posts: 1,022
on: Jun 24, 2018
Scores on a recent national statistics exam were normally distributed with a mean of 80 and a standard deviation of 6.
 a. What is the probability that a randomly selected exam will have a score of at least 71?
  b. What percentage of exams will have scores between 89 and 92?
  c. If the top 2.5 of test scores receive merit awards, what is the lowest score eligible for an award?
 d. If there were 334 exams with scores of at least 89, how many students took the exam?

Question 2

A random sample of 81 students at a local university showed that they work an average of 100 hours per month. The population standard deviation is known to be 27 hours. Compute a 95 confidence interval for the mean hours per month all students at the university work.


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

ynlevi

  • Sr. Member
  • ****
  • Posts: 338
Reply #1 on: Jun 24, 2018
Answer to Question 1

a. .9332
b. 4
c. 91.76
d. 5,000

Answer to Question 2

94.12 to 105.88


penza

  • Member
  • Posts: 1,022
Reply 2 on: Jun 24, 2018
Great answer, keep it coming :)

ghepp

  • Member
  • Posts: 361
Reply 3 on: Yesterday
:D TYSM

« previous next »
 

Did you know?

Asthma attacks and symptoms usually get started by specific triggers (such as viruses, allergies, gases, and air particles). You should talk to your doctor about these triggers and find ways to avoid or get rid of them.

Did you know?

Multiple sclerosis is a condition wherein the body's nervous system is weakened by an autoimmune reaction that attacks the myelin sheaths of neurons.

Did you know?

People with alcoholism are at a much greater risk of malnutrition than are other people and usually exhibit low levels of most vitamins (especially folic acid). This is because alcohol often takes the place of 50% of their daily intake of calories, with little nutritional value contained in it.

Did you know?

Approximately 500,000 babies are born each year in the United States to teenage mothers.

Did you know?

The B-complex vitamins and vitamin C are not stored in the body and must be replaced each day.

The endocrine glands of the endocrine system are distributed throughout the body. The endocrine glands of the endocrine system are distributed throughout the body.
Lumbar Spine Exam Reminder Lumbar Spine Exam Reminder
Video: Electromagnetic Spectrum, Chlorophyll and Pigment & Light

For a complete list of videos, visit our video library