superfly903
07.04.2020 •
Mathematics
A survey among students at a certain university revealed that the number of hours spent studying the week before final exams was approximately normally distributed with mean 25 and standard deviation 6. What proportion of students studied between 25 and 34 hours
Solved
Show answers
More tips
- F Food and Cooking What Foods Can Nursing Moms Eat?...
- L Leisure and Entertainment Choosing the Right Books to Read: Tips and Recommendations...
- L Leisure and Entertainment Couchsurfing: A New Way to Travel...
- G Goods and services Which TV is better - LCD or Plasma?...
- S Sport How to Learn to Pull Up on Monkey Bars?...
- L Leisure and Entertainment Scrapbooking: What is it and Why is it Becoming More Popular?...
- C Computers and Internet Where did torrents.ru move to?...
- B Business and Finance Understanding Cash Flow: What It Is and How It Works...
- C Computers and Internet What Are Peers and Seeds in Torrenting?...
- H Health and Medicine 10 Simple Techniques on How to Boost Your Mood...
Answers on questions: Mathematics
- M Mathematics Lines m and n are cut by transversal l. Which angle relationships are correct? Check all that apply....
- M Mathematics Water is dripping from a faucet into a glass....
- M Mathematics BRAINLIEST to correct answer!!...
- M Mathematics Work out the size of angle A...
- M Mathematics Help Please One Mixed Fraction 9/14 x 2 1/2...
- M Mathematics What are the domain and range of the function?...
- M Mathematics Twice as many hamsters as cats four legs fish...
- M Mathematics A scuba diver dove to a shipwreck 15 ⅓ feet below sea level. The diver descended ¾ of a foot each minute for the first 8 minutes. What was the diver’s depth after the...
- M Mathematics The table shows information about 1065 students. Th Th Male Female Year 7 126 109 Year 8 112 134 Year 9 121 114 Year 10 87 94 Year 11 88 80 Elena takes a stratified...
- M Mathematics When a positive integer n is written on a blackboard, an allowed operation is to substitute it with the number ab, where n= a+b, and both a and b are positive integers....
Ответ:
And we can find this probability with this difference:
And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem'
Let X the random variable that represent the hous spent studying the week before final exams of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability with this difference:
And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.
Ответ: