A random sample of math majors taking an introductory statistics course were surveyed after completing the final exam. They were asked, "How many times did you review your final exam before handing it in to the professor?" The results are displayed in a probability density function for the random variable X, the number of times students reviewed their exam before handing it in. Find the standard deviation of X. Round the final answer to two decimal places. x P(X = x) 1 1/5 2 2/5 7 2/5

Answer:

4

Step-by-step explanation:

m=(y2-y1)/(x2-x1)

m=(6-(-2))/(3-1)

m=8/2

m=4

Answer:

b. non-directional

Step-by-step explanation:

A directional hypothesis can be described as a hypothesis which predicts the direction of impact, either positive or negative, of one variable, especially independent variable, on the other variable which is known as an independent variable. For example, the hypothesis "age reduces memory performance" is a directional hypothesis. The reason is that "reduces" show the direction that age has a negative effect on memory performance.

On the other hand, non-directional hypothesis can be described as a hypothesis that does not predict the direction of impact but only states the relationship between two variables. For example, the research hypothesis is in the question that "age is related to memory performance" is non-directional hypothesis. This because the word "related" in the hypothesis only indicate that there is a relationship between the two variables, not the direction of effect of one variable on the other.

Answer:

270

Step-by-step explanation:

For any arithmetic sequence

nth term is given by

nth term = a + (n-1)d

where a is first term,

d is common difference

d is given by nth term - (n-1)th term

sum of n terms given by

sum = n/2(2a + (n-1)d)

________________________________________________

Given arithmetic sequence

-2,0,2,4,6,8...

first term a = -2

lets take third term as nth term and second term as (n-1)th term to find common difference d.

d = 2 - 0 = 2

using a = -2 , d = 2, n = 18

thus, sum of first 18 terms = n/2(2a + (n-1)d)

                                           =18/2( 2*(-2) + (18-1) 2)

                                           =9 ( -4 + 34)

                                           =9 ( 30) = 270

Thus, sum of first 18 terms is 270.

Answer:

A.

Step-by-step explanation:

A quadrilateral inscribed in a circle has its opposite angles adding up to 180°

So

<NOP + <M = 180

4x+8x-24 = 180

12x = 180+24

12x = 204

Dividing both sides by 12

x = 17

<NOP = 4(17)

= 68°

Answer:

10-19 ⇒ 4

40-49 ⇒ 3

Answer:

10-19: 4 numbers

40-49: 3 numbers

Step-by-step explanation:

10-19: 11, 13, 17, 18 (4 numbers)

40-49: 41, 44, 47 (3 numbers)

Answer:

There are many. Two examples are

[tex]f(x) = x, \\f(x) = x^3[/tex]

Step-by-step explanation:

There are many examples. The simplest is

1 -

[tex]f(x) = x[/tex]

It is trivial that

[tex]\text{if \,\,\,\,} f(x) = f(y) \,\,\,\,\,\text{then} \,\,\,\,\, x=y[/tex]

2 -

[tex]f(x) = x^3[/tex]

That function is injective as well.

[tex]\text{if \,\,\,\,} x^3 = y^3 \,\,\,\,\,\text{then} \,\,\,\,\, x=y[/tex]

An example of a function that is NOT injective is

[tex]f(x) = x^2[/tex]

Notice that

[tex]f(-2) = (-2)^2 = 2^2 = 4[/tex]

Answer:

meh

Step-by-step explanation:

Answer:

4

Step-by-step explanation:

The x-intercept occurs when y=0, if you think about it graphically.  Plug y=o into your equation:

10x - 5(0) = 40

10x = 40 (divide each side by 10)

x=4

Answer:

[tex] P(X \leq 1)= P(X=0) +P(X=1) [/tex]

And using the probability mass function we can find the individual probabiities

[tex]P(X=0)=(15C0)(0.82)^0 (1-0.82)^{15-0}=6.75x10^{-12}[/tex]

[tex]P(X=1)=(15C1)(0.82)^1 (1-0.82)^{15-1}=4.61x10^{-10}[/tex]

And replacing we got:

[tex] P(X \leq 1)= P(X=0) +P(X=1)= 4.68x10^{-10}[/tex]

And for this case yes we can conclude that 1 a significantly low number of adults requiring eyesight​ correction in a sample of 15 since the probability obtained is very near to 0

Step-by-step explanation:

Let X the random variable of interest "number of adults who need correction", on this case we now that:

[tex]X \sim Binom(n=15, p=0.82)[/tex]

The probability mass function for the Binomial distribution is given as:

[tex]P(X)=(nCx)(p)^x (1-p)^{n-x}[/tex]

Where (nCx) means combinatory and it's given by this formula:

[tex]nCx=\frac{n!}{(n-x)! x!}[/tex]

We want to find this probability:

[tex] P(X \leq 1)= P(X=0) +P(X=1) [/tex]

And using the probability mass function we can find the individual probabiities

[tex]P(X=0)=(15C0)(0.82)^0 (1-0.82)^{15-0}=6.75x10^{-12}[/tex]

[tex]P(X=1)=(15C1)(0.82)^1 (1-0.82)^{15-1}=4.61x10^{-10}[/tex]

And replacing we got:

[tex] P(X \leq 1)= P(X=0) +P(X=1)= 4.68x10^{-10}[/tex]

And for this case yes we can conclude that 1 a significantly low number of adults requiring eyesight​ correction in a sample of 15 since the probability obtained is very near to 0

Answer:1977.60

Step-by-step explanation:

24x8= 192

192x 10.30= 1977.60

Answer:

1 flowers

Step-by-step explanation:

The graph shows that only one flower received more than [tex]4\frac{1}{2}[/tex] cups of water and that is the plant that received 5 cups of water.

1 flower

Step-by-step explanation:

the question asks for flowers above the 4 1/2 mark and only 1 flower is there.

Step-by-step explanation:

let speed of freight train be x

speed of passenger train = x+6

Passenger train distance = 280 miles

freight train 250 milesthe times taken for these distances is the same

280/(x+6)=250/x

280x=250(x+6)

280x=250x+1500

30x = 1500

x= 50 mph the speed of freight train.

x+6= 50+6 = 56mph = speed of passenger train.

Answer:

[tex]\dfrac{y^2}{225} -\dfrac{x^2}{216}=1[/tex]

Step-by-step explanation:

For a hyperbolic mirror the two foci are 42 cm apart.

The distance between the foci = 2c.

Therefore:

The distance of the vertex from one focus = 6 cm

The distance of the vertex from the other focus = 36 cm

2a=36-6=30

Now:

[tex]c^2=a^2+b^2\\21^2=15^2+b^2\\b^2=21^2-15^2\\b^2=216\\b=6\sqrt{6}[/tex]

If the transverse axis lies on the y-axis, and the hyperbola is centered at the origin. Then the hyperbola has an equation of the form:

[tex]\dfrac{y^2}{a^2} -\dfrac{x^2}{b^2}=1[/tex]

Therefore, the equation of the hyperbola is:

[tex]\dfrac{y^2}{225} -\dfrac{x^2}{216}=1[/tex]

Answer: Jose should have the factory make 50 FS20 stereo tuners and 14 S100 stereo tuners each week to make the most profit

Step-by-step explanation:

Since each S100 takes 8 ounces of plastic and 4 ounces of metal. Each FS20 requires 4 ounces of plastic and 6 ounces of metal. And the factory has 312 ounces of plastic, 372 ounces of metal available, then,

For plastic

8 ounces + 4 ounces = 12 ounces

The number of stereo tuners it can produce will be

312/12 = 26 stereo tuners

For metal

4 ounces + 6 ounces = 10 ounces

The number of stereo tuners it can produce will be

372/10 = 37.2 = 37 approximately

Since FS20 generate more profit than S100, let assume that Jose produces 50 FS20 by consuming

4 × 50 = 200 ounces of plastic

6 × 50 = 300 ounces of metal

The remaining plastic will be

312 - 200 = 112

The remaining plastic will be

372 - 300 = 72

Divide 112 by 8 in order to make S100

112/8 = 14

Also 72/4 = 18.

Therefore, Jose should have the factory make 50 FS20 stereo tuners and 14 S100 stereo tuners each week to make the most profit

Answer:

4037.3264$

Step-by-step explanation:

Total amount of money after 6 years:

A = P x (1 + rate)^time    

   = 9400 x ( 1 + (6/100)/4)^(6 x 4)    

   = 13437.3264$

=> Total amount of interest after 6 years:

I  = A - P = 13437.3264 - 9400 = 4037.3264$

Answer:

Intervals = (1,064) , (1,036)

Step-by-step explanation:

Given:

Use 95% method

Mean = 1,050

Standard deviation = 7

Find:

Intervals.

Computation:

95% method.

⇒ Intervals = Mean ± 2(Standard deviation)

⇒ Intervals = 1,050 ± 2(7)

⇒Intervals = 1,050 ± 14

⇒ Intervals = (1,050 + 14) , (1,050 - 14)

⇒ Intervals = (1,064) , (1,036)

The Intervals = (1,064) , (1,036)

Given that:

Based on the above information, the calculation is as follows:

Intervals = Mean ± 2(Standard deviation)

Intervals = 1,050 ± 2(7)

Intervals = 1,050 ± 14

Intervals = (1,050 + 14) , (1,050 - 14)

Intervals = (1,064) , (1,036)

Learn more: https://brainly.com/question/1368131?referrer=searchResults

Answer:

  Find the places where the derivative is zero and the second derivative is positive.

Step-by-step explanation:

By definition, a function has a minimum where the first derivative is zero and the second derivative is positive.

That will be a "local" minimum if there are other points on the function graph that have values less than that. It will be a "global" minimum if there are no other function values less than that. A global minimum is also a local minimum.

__

On a graph, a local minimum is the bottom of the "U" where the graph changes from negative slope to positive slope.

Answer:

3 3/5 hours.

Step-by-step explanation:

There are 3 students who logged 1 1/5 so:

[tex]1\frac{1}{5} +1\frac{1}{5} +1\frac{1}{5} =3\frac{3}{5}[/tex]

3 3/5 hours have been logged total by those who logged 1 1/5 hours.

Answer:

The 99% confidence interval for the percentage of Phoenix residents who support mandatory sick leave for food handlers is between 85.40% and 92.60%.

Step-by-step explanation:

Confidence interval for the proportion:

In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which

z is the zscore that has a pvalue of [tex]1 - \frac{\alpha}{2}[/tex].

For this problem, we have that:

[tex]n = 500, \pi = \frac{445}{500} = 0.89[/tex]

99% confidence level

So [tex]\alpha = 0.01[/tex], z is the value of Z that has a pvalue of [tex]1 - \frac{0.01}{2} = 0.995[/tex], so [tex]Z = 2.575[/tex].

The lower limit of this interval is:

[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.89 - 2.575\sqrt{\frac{0.89*0.11}{500}} = 0.8540[/tex]

The upper limit of this interval is:

[tex]\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.89  + 2.575\sqrt{\frac{0.89*0.11}{500}} = 0.9260[/tex]

For the percentage:

Multiply the proportion by 100.

0.8540*100 = 85.40%

0.9260*100 = 92.60%

The 99% confidence interval for the percentage of Phoenix residents who support mandatory sick leave for food handlers is between 85.40% and 92.60%.

Answer:

Step-by-step explanation:

Given that, we have 1851 bullets that we KNOW are NOT MATCHES of one another. One by one they examine two bullets at a time.

So, there are 1851 bullets but each time we choose 2.

We have, N choose K = N! / K! (N-k)!

Here, N = 1851 and K = 2

Therefore, 1851 choose 2 = 1851! / 2! (1851-2)!

                                         = 1851! / 2! * 1849!

                                         = 1712175 Possible Combinations

Out of these 653 are false positive.

The chance of getting false positive is = 658 / 1712175

                                                            = 0.000384

                                                           = 0.0384 %

Therefore, The correct option is

The chance of false positive is 0.0384% Because this probability is sufficiently small (< or = 1%) There is high confidence in the agency's forensic evidence.

Answer:

C ; A

Step-by-step explanation:

Question 30:

Perimeter is the sum of all sides.

Perimeter for a recatngle can be found with the formula:

2(L+W)

Length is 7

Width is 4

Plug our values in.

2(7+4)

2(11)

22

Answer C

Question 31:

Circumference of a circle can be found with the formula:

πd.

Diameter of the given circle is 6.

Plug it in

6π

Round π to 3.14

6(3.14)

18.84

Answer A

Answer:

[tex]V = \frac13 \pi r^2 h[/tex]

117.81

Step-by-step explanation:

r is half the diameter so 2.5 cm

h is 18

fill in and get:

V = [tex]\frac13 \pi \cdot 6.25 \cdot 18 \approx 117.81 cm^3[/tex]

Answer:

x>-1

Step-by-step explanation:

Answer:

x > -1

Step-by-step explanation:

First we need to determine what sign this inequality uses:

Here we have an open circle so we know our sign will either be > or <

Our point is on the -1, and the arrow points in the direction of the sign as long as the variable x is on the left side of the answer

So the arrow is point to the right, indicating our sign will also be "pointing" to the right (>)

The inequality of this graph reads: x > -1

Answer:

  c)  x = 6, y = 9

Step-by-step explanation:

The figure is a parallelogram. The diagonals of a parallelogram bisect each other, so each part of a given diagonal is equal to the other part.

  3x = 2y

  2x = y+3

__

Solving the second equation for y, we have ...

  y = 2x -3

Substituting into the first equation gives ...

  3x = 2(2x -3)

  3x = 4x -6 . . . . simplify

  6 = x . . . . . . . . .add 6 -3x

  y = 2(6) -3 = 9 . . . . use the above expression for y

The values of x and y are (x, y) = (6, 9).

Answer:

Step-by-step explanation:

Two sides and the angle between are marked as congruent. That immediately tells you that the Side-Angle-Side (SAS) theorem of congruence applies.

The angle is a right angle, which makes the adjacent sides be "legs" of the right triangle. Then the Leg-Leg (LL) theorem of congruence for a right triangle also applies.

Appropriate choices are ...

  SAS, LL

Answer:

The mean of depth is 12.75cm.

The variance of depth is of 13.02 cm².

Step-by-step explanation:

An uniform probability is a case of probability in which each outcome is equally as likely.

For this situation, we have a lower limit of the distribution that we call a and an upper limit that we call b.

The mean of the uniform distribution is:

[tex]M = \frac{a+b}{2}[/tex]

The variance of the uniform distribution is given by:

[tex]V = \frac{(b-a)^{2}}{12}[/tex]

Uniform distribution on the interval (6.5, 19)

This means that: [tex]a = 6.5, b = 19[/tex]

So

Mean:

[tex]M = \frac{6.5+19}{2} = 12.75[/tex]

The mean of depth is 12.75cm.

Variance:

[tex]V = \frac{(19 - 6.5)^{2}}{12} = 13.02[/tex]

The variance of depth is of 13.02 cm².

Answer:

12.672

Step-by-step explanation:

Answer: 37.376

Step-by-step explanation: Because  4.672 x 8 is  37.376

Answer:

[tex]P(X=5)=(7C5)(0.53)^5 (1-0.53)^{7-5}=0.194[/tex]

Then the probability that exactly 5 of them use their smartphones in meetings or classes is 0.194

Step-by-step explanation:

Let X the random variable of interest "number of adults with smartphones", on this case we now that:

[tex]X \sim Binom(n=7, p=0.53)[/tex]

The probability mass function for the Binomial distribution is given as:

[tex]P(X)=(nCx)(p)^x (1-p)^{n-x}[/tex]

Where (nCx) means combinatory and it's given by this formula:

[tex]nCx=\frac{n!}{(n-x)! x!}[/tex]

And we want to find this probability:

[tex] P(X=5)[/tex]

Using the probability mass function we got:

[tex]P(X=5)=(7C5)(0.53)^5 (1-0.53)^{7-5}=0.194[/tex]

Then the probability that exactly 5 of them use their smartphones in meetings or classes is 0.194

Answer:

Set the height of the bar to 5

Step-by-step explanation:

Since there are 5 quantities between 20-29, So set the height up to 5

Answer:

The correct answer to the following question will be "No". The further explanation is given below.

Step-by-step explanation:

Probability (Keeping the disease out of 1 contact)

= [tex]0.5[/tex]

Probability (not keeping the disease out of 1 contact)

= [tex]1-0.5[/tex]

= [tex]0.5[/tex]

Now,

Probability (not keeping the disease out of 2 contact)

= Keeping the disease out of 1 contact × not keeping the disease out of 1 contact

On putting the estimated values, we get

= [tex]0.5\times 0.5[/tex]

= [tex]0.25[/tex]

So that,

Probability (Keeping the disease out of 2 contact)

= [tex]1-0.25[/tex]

= [tex]0.75 \ i.e., 75 \ percent[/tex]

∴  Not 100%