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
Lilit [14]
3 years ago
10

Plz help Give answer!!

Mathematics
1 answer:
ivann1987 [24]3 years ago
8 0

winn because i did the math

You might be interested in
"A manufacturer of automobile batteries claims that the average length of life for its grade A battery is 55 months. Suppose the
STALIN [3.7K]

Answer:

\\ P(z>-2) = 0.97725 or P(x>49) is about 97.725% (or being less precise 97.5% using the <em>empirical rule</em>).

Step-by-step explanation:

We solve this question using the following information:

  1. We are dealing here with <em>normally distributed data</em>, that is "<em>the frequency distribution of the life length data is known to be mound-shaped</em>".
  2. The normal distribution is defined by two parameters: the population mean (\\ \mu) and the population standard deviation (\\ \sigma). In this case, we have that \\ \mu = 55 months, and \\ \sigma = 3 months.
  3. To find the probabilities, we have to use the <em>standard normal distribution</em>, which has \\ \mu = 0 and \\ \sigma = 1. The probabilities for this distribution are collected in the <em>standard normal table</em>, available in Statistics books or on the Internet. We can also use statistics programs to find these probabilities.
  4. For most cases, we need to use the <em>cumulative standard normal table, </em>and for this we have to previously "transform" a raw score (x) into a z-score using the next formula: \\ z = \frac{x - \mu}{\sigma} [1]. A z-score tells us the distance from the mean that a raw score is from it in <em>standard deviations units</em>. If this value is <em>negative</em>, the raw score is <em>below</em> the mean. Conversely, a <em>positive</em> value indicates that it is <em>above</em> the mean.
  5. The <em>cumulative standard normal table </em>is made for positive values of z. Since the normal distribution is <em>symmetrical</em> around the mean, we can find the negative values of z using this formula: \\ P(z [2].

Having all this information, we can solve the question.

<h3>The percentage of the manufacturer's grade A batteries that will last more than 49 months</h3>

<em>First Step: Use formula [1] to find the z-score of the raw score x = 49 months</em>.

\\ z = \frac{49 - 55}{3}

\\ z = \frac{-6}{3}

\\ z = -2

This means that the raw score is represented by a z-score of \\ z = -2, which tells us that it is<em> two standard deviations below</em> the population mean.

<em>Second Step: Consult this value in the cumulative standard normal table for z = 2 and apply the formula [2] to find the corresponding probability.</em>

For a z = 2, the probability is 0.97725.  

Then

\\ P(z

\\ P(z2)

\\ P(z2)

But we <em>are not asked</em> for P(z<-2) but for P(z>-2) = P(x>49). This probability is the <em>complement</em> of the previous result, that is

\\ P(z>-2) = 1 - P(z

\\ P(z>-2) = 1 - 0.02275

\\ P(z>-2) = 0.97725

That is, the "<em>percentage of the manufacturer's grade A batteries will last more than 49 months</em>" is

\\ P(z>-2) = 0.97725 or about 97.725%

A graph below shows this result.

Notice that if we had used the <em>68-95-99.7 rule</em> (also known as the <em>empirical rule</em>), that is, in a normal distribution, the interval between <em>one standard deviation below and above the mean</em> contains, approximately, 68% of the observations; the interval between <em>two standard deviations below and above the mean</em> contains, approximately, 95% of the observations; and the interval between <em>three standard deviations</em> below and above the mean contains, approximately, 99.7% of the observations, we could have concluded that 2.5 % of the manufacturer's grade A batteries will last <em>less</em> than 49 months, and, as a result, 1 - 0.025 = 0.975 or 97.5% will last more than 49 months.

We can conclude that with a less precise answer (but faster) because of the <em>symmetry of the normal distribution</em>, that is, 1 - 0.95 = 0.05. At both extremes we have 0.05/2 = 0.025 or 2.5% and we were asked for P(x>49) = P(z>-2) (see the graph below).

6 0
3 years ago
Sally has been measuring the tree in her yard for a science project. The tree has grown 12 of an inch each month and grown a tot
hammer [34]

Answer:

Sally has been measuring the tree for 4 months

Step-by-step explanation:

The correct question is as follows;

Sally has been measuring the tree in her yard for a science project. The tree has grown 1/2 of an inch each month and grown a total of 2 inches taller. How many months has Sally been measuring this tree?

.........................................................................................

Solution;

The tree has grown 1/2 of an inch each month and has grown a total of 2 inch taller.

We now need to know the number of months in which the measuring has been taking place.

To know the number of months, we simply need to divide the change in height which is 2 inch by the individual month growth rate which is 1/2 inch

So mathematically, that would be 2/1/2 = 2 * 2 = 4 months

3 0
3 years ago
Andrew is a realtor who makes 11% commissions. if he recently sold a house for $120,000 how much would he make in commissions
vova2212 [387]

Answer:

the answer would be 133200 dollars

5 0
2 years ago
Which equation has the solutions x = startfraction 5 plus-or-minus 2 startroot 7 endroot over 3 endfraction?
Shtirlitz [24]

The equation that has the solution x = \frac{5 \pm \sqrt{7}}{3} is 3x^2 - 10x + 6 = 0

<h3>How to determine the equation?</h3>

The solution is given as:

x = \frac{5 \pm \sqrt{7}}{3}

The solution to a quadratic equation is

x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

By comparing both equations, we have:

-b = 5

b^2 - 4ac = 7

2a = 3

Solve for b in -b = 5

b = -5

Solve for a in 2a = 3

a = 1.5

Substitute values for a and b in b^2 - 4ac = 7

(-5)^2 - 4 * 1.5c = 7

Evaluate

25 - 6c = 7

Subtract 25 from both sides

-6c = -18

Divide by - 6

c = 3

So, we have:

a = 1.5

b =  -5

c = 3

A quadratic equation is represented as:

ax^2 + bx + c = 0

So, we have:

1.5x^2 - 5x +3 = 0

Multiply through by 2

3x^2 - 10x + 6 = 0

Hence, the equation that has the solution x = \frac{5 \pm \sqrt{7}}{3} is 3x^2 - 10x + 6 = 0

Read more about quadratic equation at:

brainly.com/question/1214333

#SPJ1

7 0
2 years ago
Ann rolls a 6 sided number cube and then chooses a card from a set numbered 1 through 9. What is the probability that she will r
Licemer1 [7]
5/9 to chose odd card, 3/6 to roll even number
6 0
3 years ago
Other questions:
  • a bag contains 5 red marbles 4 blue marbles and 6 yellow marbles if 3 marbles are selected in succession what is the probability
    8·1 answer
  • Which of thr following represents the most accurate estimation of 4 8?
    9·1 answer
  • John is comparing the prices of two bags of the
    14·1 answer
  • The product of any interger and 2 is greater than 2 what is the answer
    12·2 answers
  • Nellie is analyzing a quadratic function f(x) and a linear function g(x). Will they intersect?
    10·1 answer
  • Using Ratios to Solve Problems - Item 1457 Question 4 of 7 Evan's family drove to a theme park for vacation. They drove the same
    8·1 answer
  • Use the distributive property to simplify this expression -(5-3v)
    8·1 answer
  • Problem 44. The sum of a certain quantity "p" together with two-third of that number, and one-third of that number, becomes 234.
    10·1 answer
  • Raymond’s gas tank is 1/3 full. After he buys 11 gallons of gas, it is 5/6 full. How many gallons can Raymond’s tank hold?
    9·1 answer
  • How can i get $41.11 with onlly 3 bills and 8 coins
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!