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 76 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
Thanks for the timely response, appreciate it

brbarasa

  • Member
  • Posts: 308
Reply 3 on: Yesterday
Wow, this really help

« previous next »
 

Did you know?

Amphetamine poisoning can cause intravascular coagulation, circulatory collapse, rhabdomyolysis, ischemic colitis, acute psychosis, hyperthermia, respiratory distress syndrome, and pericarditis.

Did you know?

Carbamazepine can interfere with the results of home pregnancy tests. If you are taking carbamazepine, do not try to test for pregnancy at home.

Did you know?

On average, the stomach produces 2 L of hydrochloric acid per day.

Did you know?

Vaccines cause herd immunity. If the majority of people in a community have been vaccinated against a disease, an unvaccinated person is less likely to get the disease since others are less likely to become sick from it and spread the disease.

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.

Tropical deciduous forest in Bandhavgarh National Park, India Tropical deciduous forest in Bandhavgarh National Park, India
Young recent immigrants often develop two identities Young recent immigrants often develop two identities
Video: Body plan of euglena Animation

For a complete list of videos, visit our video library