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 103 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
:D TYSM

carojassy25

  • Member
  • Posts: 299
Reply 3 on: Yesterday
YES! Correct, THANKS for helping me on my review

« previous next »
 

Did you know?

Malaria was not eliminated in the United States until 1951. The term eliminated means that no new cases arise in a country for 3 years.

Did you know?

Patients who have been on total parenteral nutrition for more than a few days may need to have foods gradually reintroduced to give the digestive tract time to start working again.

Did you know?

Multiple experimental evidences have confirmed that at the molecular level, cancer is caused by lesions in cellular DNA.

Did you know?

Each year in the United States, there are approximately six million pregnancies. This means that at any one time, about 4% of women in the United States are pregnant.

Did you know?

More than 50% of American adults have oral herpes, which is commonly known as "cold sores" or "fever blisters." The herpes virus can be active on the skin surface without showing any signs or causing any symptoms.

Stag and hinds in Killarney National Park, Co. Kerry, Ireland. Stag and hinds in Killarney National Park, Co. Kerry, Ireland.
When the IQ scores of identical twins differ, behavior genetics researchers attribute these to ... When the IQ scores of identical twins differ, behavior genetics researchers attribute these to ...
An exam question about chromosomes and alleles An exam question about chromosomes and alleles
Video: Frequency of stimulation and force (Recruitment of motor units and force)

For a complete list of videos, visit our video library