1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
seraphim [82]
3 years ago
13

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
Mathematics
1 answer:
Rainbow [258]3 years ago
6 0

Answer:

P(25

And we can find this probability with this difference:

P(0

And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.  

P(0

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:

X \sim N(25,6)  

Where \mu=25 and \sigma=6

We are interested on this probability

P(25

And the best way to solve this problem is using the normal standard distribution and the z score given by:

z=\frac{x-\mu}{\sigma}

If we apply this formula to our probability we got this:

P(25

And we can find this probability with this difference:

P(0

And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.  

P(0

You might be interested in
HELP HELP HELP HELP HELP PELADE PLEASE PLEASE IM DESPERATE SNSMXMDMAK
Vera_Pavlovna [14]

Answer:

  see below

Step-by-step explanation:

The points at the corners of the given figure are ...

  (0, 0), (0, 4), (3, 4), (3, 0)

When the figure is scaled by a factor of 1/3, each of the coordinates is multiplied by 1/3:

  (0, 0), (0, 4/3), (1, 4/3), (1, 0) . . . . . points scaled by 1/3

When the figure is scaled by a factor of 3/2, each of the coordinates is multiplied by 3/2:

  (0, 0), (0, 6), (9/2, 6), (9/2, 0) . . . . . . points scaled by 3/2

__

The points that are on your list are shown in bold above.

6 0
3 years ago
The midpoint of AB is M(1, 3). If the coordinates of A are(4,1), what are the coordinates of B?
Oxana [17]

Answer:

B(-2,5)

Step-by-step explanation:

\frac{x + 4}{2}  = 1 \\ 2 \times  \frac{x + 4}{2}  = 1 \times 2 \\ x + 4 = 2 \\ x = 2 - 4 \\ x =  - 2 \\  \frac{y + 1}{2}  = 3 \\ 2 \times  \frac{y + 1}{2}  = 3 \times 2 \\ y + 1 = 6 \\ y = 6  -  1 \\ y = 5

Hope that this is helpful.

Have a nice day.

6 0
2 years ago
When the expression $-2x^2-20x-53$ is written in the form $a(x+d)^2+e$, where $a$, $d$, and $e$ are constants, then what is the
Sladkaya [172]
We start with 2 x^{2} -20x-53 and wish to write it as a(x+d) ^{2} +e

First, pull 2 out from the first two terms: 2( x^{2} -10x)-53

Let’s look at what is in parenthesis. In the final form this needs to be a perfect square. Right now we have x^{2} -10x and we can obtain -10x by adding -5x and -5x. That is, we can build the following perfect square: x^{2} -10x+25=(x-5) ^{2}

The “problem” with what we just did is that we added to what was given. Let’s put the expression together. We have 2( x-5) ^{2}-53 and when we multiply that out it does not give us what we started with. It gives us 2 x^{2} -20x+50-53=2 x^{2} -20x-3

So you see our expression is not right. It should have a -53 but instead has a -3. So to correct it we need to subtract another 50.

We do this as follows: 2(x-5) ^{2}-53-50 which gives us the final expression we seek:

2(x-5) ^{2}-103

If you multiply this out you will get the exact expression we were given. This means that:
a = 2
d = -5
e =  -103

We are asked for the sum of a, d and e which is 2 + (-5) + (-103) = -106


7 0
3 years ago
Please solve this problem. I can't solve it! And can someone explain how to do it please??
s2008m [1.1K]

Answer:

1.23

Step-by-step explanation:

They already give u the amount of oz in a gram, so you would want to multiply 0.035 by 37.

6 0
3 years ago
John's goal is to have more then -7 dollars in his bank account by the end of the month.The variable d is the number of dollars
Alona [7]

Answer:

i need more info

Step-by-step explanation:

6 0
3 years ago
Read 2 more answers
Other questions:
  • Thomas bought a new backpack that was 30% off the original price. The sale resulted in a $15 discount. What was the original pri
    10·1 answer
  • Today, Nate has 100 bananas. He will eat 2 of them every day.
    7·2 answers
  • Cot^2 x- 6cotx - 5=0
    14·1 answer
  • A laser bean anchored in a wall originates 4 feet from the ground and is aimed at a mirror on the floor 6 feet from the wall. Th
    5·2 answers
  • If the first quadrant you start at 3,6 and move 3 units down
    10·1 answer
  • A khanacademy.org Differential equations: exponential model word problems You might need: Calculator A controversial story comes
    13·1 answer
  • Devaughn is 14 years younger than Sydney. The sum of their ages is 76. What is Sydney's age?​
    15·2 answers
  • Let’s work with some actual data this time. Go online to research and find a set of real-world data in two variables. The data c
    10·2 answers
  • A circle has a circumference of 69.08 feet What is the of the circle? Use 3.14 for
    15·1 answer
  • <img src="https://tex.z-dn.net/?f=6%20%5Csqrt%7B2%7D%20%20-%204%20%5Csqrt%7B3%7D%20%20%2B%20%20%7C3%20%5Csqrt%7B8%7D%20-%208%20%
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!