It has been observed that some persons who suffer acute heartburn, again suffer acute heartburn within one year of the first episode. This is due, in part, to damage from the first episode. The performance of a new drug designed to prevent a second episode is to be tested for its effectiveness in preventing a second episode. In order to do this two groups of people suffering a first episode are selected. There are 55 people in the first group and this group will be administered the new drug. There are 45 people in the second group and this group will be administered a placebo. After one year, 11% of the first group has a second episode and 9% of the second group has a second episode. Conduct a hypothesis test to determine, at the significance level 0.1, whether there is reason to believe that the true percentage of those in the first group who suffer a second episode is different from the true percentage of those in the second group who suffer a second episode?

Answers

Answer 1

Answer:

Null hypothesis :

[tex]H_o:p_1-p_2 = 0[/tex]

Alternative hypothesis:

[tex]H_1:p_1-p_2 \neq 0[/tex]

Decision Rule:

To reject the null hypothesis if  z < -1.65 and z > 1.65

Conclusion:

Failed to reject null hypothesis if z > -1.65 or z < 1.65

z -value = 0.33022

P-value = 0.7414

Decision Rule:

Since the P-value is higher than the level of significance , therefore do not reject the null hypothesis at the level of significance of 0.1

Conclusion:  we failed to reject null hypothesis, Therefore, the data does not believe that the true percentage of those in the first group who suffer a second episode is different from the true percentage of those in the second group who suffer a second episode

Step-by-step explanation:

From the summary of the given statistical data sets.

Let consider to [tex]p_1[/tex] represent percentage of the first group ; &

[tex]p_2[/tex] represent percentage of the second group

The null and the alternative hypothesis can be stated s follows:

Null hypothesis :

[tex]H_o:p_1-p_2 = 0[/tex]

Alternative hypothesis:

[tex]H_1:p_1-p_2 \neq 0[/tex]

At the level of significance ∝ = 0.1; the two tailed critical value from the z-table

[tex]z_{\alpha/2} = 1.65[/tex]

Decision Rule:

To reject the null hypothesis if  z < -1.65 and z > 1.65

Conclusion:

Failed to reject null hypothesis if z > -1.65 or z < 1.65

However; from the question:

There are 55 people in the first group and this group will be administered the new drug.

There are 45 people in the second group and this group will be administered a placebo.

After one year, 11% of the first group has a second episode and 9% of the second group has a second episode.

The test statistic for the for the first group who suffered from the second episode can be denoted as :

[tex]\hat p_1 = \dfrac{\overline x_1}{n_1}=0.11[/tex]

The test statistic for the for the second group who suffered from the second episode can be denoted as :

[tex]\hat p_2 = \dfrac{\overline x_2}{n_2}=0.09[/tex]

where;

[tex]n_1[/tex] = sample size of group 1 = 55

[tex]n_2[/tex] = sample size of group 2 = 45

The total probability of both group is :

[tex]\hat p = \dfrac{n_1 \hat p_1 + n_2 \hat p_2}{n_1 + n_2}[/tex]

[tex]\hat p = \dfrac{55*0.11+ 45 * 0.09}{55+45}[/tex]

[tex]\hat p = \dfrac{6.05+ 4.05}{100}[/tex]

[tex]\hat p = \dfrac{10.1}{100}[/tex]

[tex]\hat p = 0.101[/tex]

The standard error of the statistic [tex]\hat p_1 - \hat p_2[/tex] an be computed as follows:

[tex]S.E(\hat p_1 - \hat p_2)= \sqrt{ p_1 (1 - \hat p)( \dfrac{1}{n_1}+\dfrac{1}{n_2})}[/tex]

[tex]S.E(\hat p_1 - \hat p_2)= \sqrt{0.101 (1 - 0.101)( \dfrac{1}{55}+\dfrac{1}{45})}[/tex]

[tex]S.E(\hat p_1 - \hat p_2)= \sqrt{0.101(0.899)(0.0404)}[/tex]

[tex]S.E(\hat p_1 - \hat p_2)= \sqrt{0.0036682796}[/tex]

[tex]S.E(\hat p_1 - \hat p_2)=0.060566[/tex]

Now; The test statistics is determined to be :

[tex]z = \dfrac{(\hat p_1 - \hat p_2 ) - (p_1-p_2)}{SE(\hat p_1 - \hat p_2)}[/tex]

[tex]z = \dfrac{(0.11-0.09) - 0}{0.060566}[/tex]

z = 0.33022

Hence; the value for the test statistics =  0.33022

the value for the test statistics =  0.33

From the z value; The P-value for the test statistics can be computed as:

P-value = 2P(Z ≥ |z|)

P-value = 2P(Z ≥  0.33022)

P-value = 2 × P (Z ≤ - 0.33022)

From the z table Z ≤ - 0.33022 = 0.3707

P-value = 2 × 0.3707

P-value = 0.7414

Decision Rule:

Since the P-value is higher than the level of significance , therefore do not reject the null hypothesis at the level of significance of 0.1

Conclusion:  we failed to reject null hypothesis, Therefore, the data does not believe that the true percentage of those in the first group who suffer a second episode is different from the true percentage of those in the second group who suffer a second episode


Related Questions

WILL MARK BRAINLIST----- A particular map shows a scale of 1 cm:5 km. What would the map distance be (in cm) if the actual distance to be represented is 14 km?

Answers

Answer:

2.8 cm

Step-by-step explanation:

The map scale is 1 cm : 5 km. That means that 1 cm is equal to 5 km.

To find the map distance (in cm), we have to set up a ratio.

[tex]\frac{1 cm}{5 km} = \frac{x}{14 km}[/tex]

X (the map distance in cm) is over the actual distance of 14 km.

Now cross multiply and divide.

[tex]5x = 14[/tex]

[tex]\frac{5x}{5} = \frac{14}{5}[/tex]

[tex]x = 2.8 cm[/tex]

If the actual distance to be represented is 14 km, the map distance (in cm) will be 2.8 cm.

Hope that helps.

Find a solution to the linear equation y=−x+7 by filling in the boxes with a valid value of x and y.

Answers

Answer:

(0,7) and (7,0)

Step-by-step explanation:

When x = 0, y = 7

When y = 0, x = 7

The solution to this equation is: (0,7) and (7,0) and can be graphed on a cartesian plane like the attached graph.

trang can test message about 38 words per minute. if she types at this rate for 20 minutes about how many words will she type?

Answers

Answer:

760 words for 20 minutes.

Step-by-step explanation:

38 words = 1 minute

1 x 20 = 20

38 x 20 = 760 words

(6/22 + 5/77) ^2 equalviant to in fraction form

Answers

Answer:

676/5929

Step-by-step explanation:

Use the given information to find the ​p-value. ​Also, use a 0.05 significance level and state the conclusion about the null hypothesis​ (reject the null hypothesis or fail to reject the null​ hypothesis). With Upper H1​: p≠​0.377, the test statistic is z=3.06.

a. 0.0022; fail to reject the null hypothesis
b. 0.0011; reject the null hypothesis
c. 0.0022; reject the null hypothesis
d. 0.0011; fail to reject the null hypothesis

Answers

Answer:

Option c: 0.0022; reject the null hypothesis

Step-by-step explanation:

Using a p value calculator, with a z score of 3.06 at 0.05 level of significance for a two tailed test, the p-value is 0.002213. This value is lower than 0.05 thus the result is significant we will reject the null hypothesis.

To calculate the p value by hand, we do this

The test statistic is 3.06. Since the test possesses a not equal to alternative, we look up the test statistic on the z table find the corresponding probability. Thus we have 3.06 - on the z table - 0.99889

Then we subtract from 1 and double it

1-0.99889 = 0.00111 x 2 = 0.0022.

Solve x is less than or equal to 0 and x is greater than or equal to -4

Answers

Answer:

x = {-3, -2, -1, 0}

Step-by-step explanation:

x ≤ 0

x > -4

then

x {-3, -2, -1, 0}

Cell phone bills for residents of have a mean of $47/line with a standard deviation of $9/line. Find the probability that the average cost/line for the Math

Answers

Dive 9 by 47 to reach ur medium I believe 28

H0:p=0.45 ; Ha:p>0.45
The p-value for this hypothesis test is 0.025.
The level of significance is α=0.05

Select the correct answer below:

a. There is sufficient evidence to conclude that the proportion of agenda-less meetings is greater than 45%.
b. There is NOT sufficient evidence to conclude that the proportion of agenda-less meetings isgreater than 45%.
c. There is sufficient evidence to conclude that the proportion of agenda-less meetings is greater than 55%.
d. There is NOT sufficient evidence to conclude that the proportion of agenda-less meetings is greater than 55%.

Answers

Answer:

Option A is correct

Step-by-step explanation:

From the question we are told that

  The  Null Hypothesis  is  [tex]H_o : p = 0.45[/tex]

   The alternative hypothesis [tex]H_a : p > 0.45[/tex]

   The  level of significance is  [tex]\alpha = 0.05[/tex]

    The  p-value is  [tex]p-value = 0.025[/tex]

Now looking at the given data we see that the the p-value is less than [tex]\alpha[/tex]

Generally when this occurs in a hypothesis test we reject the null hypothesis which mean that the result which we obtain is statistically significant.

Hence the alternative hypothesis is correct, which means that,

  There is sufficient evidence to conclude that the proportion of agenda-less meetings is greater than 45%. which is option A

The test statistic of z=1.92 is obtained when testing the claim that p≠0.767. a. Identify the hypothesis test as being​ two-tailed, left-tailed, or​ right-tailed. b. Find the​ P-value. c. Using a significance level of α=0.10​, should we reject H0 or should we fail to reject H0​?

Answers

Answer:

it is a two tailed test

The p - value for z=1.92  is 0.9726

Using a significance level of α=0.10, We fail to reject H0. The calculated z value lies out side the Zα value.

Step-by-step explanation:

For p≠0.767

Taking  null hypothesis as p≠0.767 and alternate hypothesis as p =0.767

H0 :p≠0.767  Ha :p≠0.767  it is a two tailed test

The p - value for z=1.92  is 0.9726 from the table.

Using a significance level of α=0.10

z value for 0.10 for two tailed test is ± 1.645

Z >zα

1.92> ± 1.645

Using a significance level of α=0.10, We fail to reject H0. The calculated z value lies out side the Zα value.

if my grade is 69% what will my grade be if i got a 3.3 of 4 on a essay and it's worth 25% of my grade?​

Answers

Answer:

72.4%

Step-by-step explanation:

The essay is 25% of your grade, and the rest is 75% of your grade.

25 (3.3/4) + 75 (0.69) ≈ 72.4

Solve for x: ( 1/2 )^(x−1)=2^(3x−4)

Answers

Answer:

[tex]\huge\boxed{x=\dfrac{5}{4}}[/tex]

Step-by-step explanation:

[tex]\left(\dfrac{1}{2}\right)^{x-1}=2^{3x-4}\qquad\text{use}\ a^{-1}=\dfrac{1}{a}\\\\\left(2^{-1}\right)^{x-1}=2^{3x-4}\qquad\text{use}\ (a^n)^m=a^{nm}\\\\2^{(-1)(x-1)}=2^{3x-4}\qquad\text{use the distributive property}:\ a(b+c)=ab+ac\\\\2^{(-1)(x)+(-1)(-1)}=2^{3x-4}\\\\2^{-x+1}=2^{3x-4}\iff-x+1=3x-4\qquad\text{subtract 1 from both sides}\\\\-x+1-1=3x-4-1\\\\-x=3x-5\qquad\text{subtract}\ 3x\ \text{from both sides}\\\\-x-3x=3x-3x-5\\\\-4x=-5\qquad\text{divide both sides by (-4)}[/tex]

[tex]\dfrac{-4x}{-4}=\dfrac{-5}{-4}\\\\x=\dfrac{5}{4}[/tex]

Help please!!!!!!! Thxxxxx

Answers

Answer:

x= 155°

straight line equals 180°

since you have a side that equals to 25°

you subtract

180°-25° = 155°

3)
Rick says he has
two miles already.
Which form of the verb best completes the sentence?
A)
ran
B)
run
C)
running
D)
runs

Answers

Step-by-step explanation:

Because the sentence is speaking that he has done already so we will use the past verb ran

Rick says he has ran two miles already

Answer:

b. run

Step-by-step explanation:

Rick says he has run two miles already

It will be "ran" if the sentence had said, "Rick 'ran' two miles already."

BRAINLIST PLS!

Daniel's mom deposits $80 into his savings account for the year. Daniel decides to upgrade his game account which costs $7 per month. How many months will Daniel be able to pay for his game account if his mom doesn't deposit any more money into his savings account?

Answers

Answer:

11.43

Step-by-step explanation:

80÷7= 11.428571428571428571428571428571

i hope this helps

What number is in between 10 and 16?

Answers

Answer:

13

Step-by-step explanation:

10 + 16 = 26

26 divided by 2 = 13

The middle number is 13

we assume you mean the number in the exact middle of the two numbers on a number line, as illustrated below, where X=10 and Y=16. Thus, the number halfway between 10 and 16 is 13

72 students choose to attend one of three after school activities: football, tennis or running.
There are 25 boys.
27 students choose football, of which 17 are girls.
18 students choose tennis.
24 girls choose running.
A student is selected at random.
What is the probability this student chose running?
Give your answer in its simplest form.

Answers

Answer:

P = 0,3749       or    P = 37,49 %

Step-by-step explanation:

17 girls play football  10 boys do   ⇒ 27 students

24 girls running  3 boys do   ⇒ 27 students

then  6 girls play tennis  and  12 boys do ⇒ 18 students

Probability of student running P is equal to P1 (probability of student (boy) running ) plus P2 (probability of student (girl) running )

P = P1  +  P2

P1 (probability of girl running ) is equal to choose a girl out of 72 students, times the probability of the girl running

Probability of girl   47/72      =   0,6528

Probability of running is equal to 24/47  = 0,5106

Then the probability of girl running is equal to

P2 = 0,6528*0,5106  =  0,3333    or   33,33 %

P2 = 0,3333    or     P2 = 33,33 %

Now we have 72 students 25 boys, then the probability of choosing a boy is  = 25/72    =  0,3472

And the probability of running is 3/25 = 0,12

Then

P1 = 0,3472*0,12

P1 = 0,04166   and

P = P1 + P2

P = 0,04166 + 0,3333

P = 0,3749       or    P = 37,49 %

The Cambridge Power and Light Company selected a random sample of 20 residential customers. Following are the amounts, to the nearest dollar, the customers were charged for electrical service last month:
53 49 54 50 21 46 75 45 63 76 61 63 36 34 54 63 37 62 66 62
(a) Compute the arithmetic mean.(Round your answer to 2 decimal places. Omit the "$" sign in your response.)
The mean is $
(b) Indicate whether it is a statistic or a parameter.

Answers

Answer:

a) the mean is $53.50

b) it is a statistic

Step-by-step explanation:

mean = ∑fx/∑f

∑f = 20

mean = (sum of the terms) ÷ (number of terms)

mean = (53+49+54+50+21+46+75+45+63+76+61+63+36+34+54+63+37+62+66+62) ÷ 20 = 1070/20

=$53.50

b) it is statistics because it is a random sample of 20 residential customers not the actual population

g The equation for the change of position of a train starting at x = 0 m is given by The dimensions of b are Select one: a. L-1T-1 b. LT-1 c. T-3 d. LT-2 e. LT-3

Answers

Answer:

B. LT⁻¹

Step-by-step explanation:

The question is incomplete. Here is the complete question,

The equation for the change of position of a train starting at x = 0 m is given by x =(1/2)at² + bt³. The dimensions of b are__

from the equation of motion given, the constant b is the velocity of the body. For us to get the dimension of b, we have to find the dimension of the velocity .

Since velocity is the rate of change of displacement of a body, then;

VELOCITY = DISPLACEMENT/TIME

displacement is measured in metres while time in seconds.

expressing the formula in terms of its fundamental unit,

v = metre/secs

Since the fundamental quantity of the metre is length (L) and that of seconds is the time (T); the dimensions is expressed as;

V = L/T

V = L * 1/T

V = L * T⁻¹

V = LT⁻¹

Hence the dimension of b is  LT⁻¹.

Note that the dimension of a body is written in terms of its fundamental quantities.

The dimensions of b from the given equation are; B: LT⁻¹

Dimensional Analysis

The complete question is;

The equation for the change of position of a train starting at x = 0 m is given by x =(1/2)at² + bt³. The dimensions of b are__

Now, in that equation above, b represents the velocity of the motion. Now, the formula for velocity is;

Velocity = Distance/Time

Now, distance is also called Length and represented by L in basic parameters units while Time is represented by T.

Thus, the dimensions of b are; L/T or expressed as LT⁻¹

Read more on dimensional analysis at; https://brainly.com/question/1528136

Perform the indicated operation. 15b/4 * 8/9a^2b^2

Answers

Answer:

The simplified expression is [tex]\frac{10}{3 a^2 b}[/tex]

Step-by-step explanation:

The given expression is:

[tex]\frac{15b}{4} * \frac{8}{9a^2 b^2}[/tex]

Multiply the items in the numerator together ( 15b * 8 = 120 b). Also multiply the items in the denominator together ( 4 * 9a²b² = 36a²b²). The expression thus becomes:

[tex]= \frac{120b}{36 a^2 b^2} \\\\[/tex]

Divide both the numerator and the denominator by 12b:

[tex]= \frac{120b /12b}{36 a^2 b^2/12b}[/tex]

The expression finally becomes:

[tex]= \frac{10}{3 a^2 b}[/tex]

Answer:

Step-by-step explanation:

here u go

A six sided number cube is rolled twice. What is the probability that the first roll is an even number and the second roll is a number grater than 4?

Answers

Answer:

1/6

Step-by-step explanation:

The probability of even number is 1/2. The probability of number greater than 4 is 1/3, because only 5 and 6 are greater than 4.

Multiply these two values

1/2*1/3= 1/6

Marcia is a bag that contains four green marbles, eight yellow marbles, and 20 red marbles. If she chooses one marble from the bag, what is the probability that the marble is not red?

Answers

Answer:

3/8

Step-by-step explanation:

The bag contains 4 green marbles, 8 yellow marbles and 20 red marbles.

The total number of marbles is 32.

She chooses one from the bag.

The probability of the marble not being red is:

P(not red) = 1 - P(red)

P(not red) = 1 - (20 / 32) = 1 - 5/8

P(not red) = 3/8

The probability of it not being red is 3/8.

N
5. Use AABC to find the value of sin B.
A 7
B
25
B 24
C
24
А
C7
25
D 24​

Answers

*see the attachment below for the missing figure

Answer:

[tex] sin B = \frac{24}{25} [/tex]

Step-by-step explanation:

Given a right angled triangle, ∆ABC

AB = 25

BC = 7

AC = 24

<ACB = 90°

Required:

Value of Sin B

Solution:

Using trigonometric ratio formula,

[tex] sin B = \frac{opposite}{hypotenuse} [/tex]

Opposite = AC = 24 (the side opposite to <B)

Hypotenuse = AB = 25 (the longest side facing the right angle)

[tex] sin B = \frac{24}{25} [/tex]

Given: AB=BC,AM=MC BM ⊥AC , EF⊥BC Prove: EC/AB = FC/MA

Answers

Answer:

90 degree EFC. and. BMC

across fc/ma

across ec/ab

6th grade math , help me please :)

Answers

Answer:

a. 4.5 grams per cup

b. 3.2 ounces per week

c. 19.2 grams per cubic centimeters

d. $3.29 per gallon

Step-by-step explanation:

The unit rate is simply a ratio comparing 2 given quantities, whereby the denominator is 1.

The unit rate of the above given problems can be determined as shown below:

a. 18 grams of salt per 4 cups, to find the unit rate, calculate how many grams of salt you'd get in 1 cup by dividing 18 by 4

[tex] \frac{18}{4} = 4.5 [/tex]

Unit rate = 4.5 grams per cup

b. 19.2 ounces is gained by the baby in 6 weeks.

Unit rate is the amount of ounces gained in 1 week

Unit rate = [tex] \frac{19.2}{6} = 3.2 [/tex]

Unit rate = 3.2 ounces per week

c. Unit rate = [tex] \frac{76.8}{4} = 19.2 [/tex]

Unit rate = 19.2 grams per cubic centimeters

d. Unit rate = [tex] \frac{23.03}{7} = 3.23 [/tex]

Unit rate = $3.29 per gallon

The graph shows government receipts and outlays​ (both on-budget and​ off-budget) for . In what years did receipts appear to climb faster than​ outlays?

Answers

Answer: Receipts appear to climb faster than outlays in 2001, 2002, 2003 and 2004

Step-by-step explanation: So if you see the graph you can see that receipts started to climb faster by the middle of 2001 so in conclusion  Receipts appear to climb faster than outlays in 2001, 2002, 2003 and 2004 hope that help you

When government revenues exceed government outlays in a particular year, this is called a d) budget surplus.

What is budget surplus?

A budget surplus occurs when a government's income from taxes and other sources of revenue exceed its expenses and spending on public programs, services, and infrastructure. A budget surplus is a positive indicator for the government's financial health as it indicates that the government is able to manage its finances well, generate more revenue than it spends, and potentially pay off any debts.

Here, we have,

In contrast, a budget deficit occurs when government spending exceeds its revenue, resulting in increased debt and a potentially negative impact on the government's credit rating.

Budget surpluses can be used to invest in public projects or programs, reduce debt, or returned to taxpayers in the form of tax cuts.

However, it is important to note that budget surpluses can also be a result of reduced spending on public programs, which can have a negative impact on social services and infrastructure.

Therefore, the correct answer is d) budget surplus.

Learn more about budget surplus here:

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coomplete question:

When government revenues exceed government outlays in a particular​ year, this is called

A.

the national debt.

B.

a budget deficit.

C.

fiscal policy.

D.

a budget surplus.

what is the solution to the system of equations?

y = 4x-10
y=2

A) (3,2)
B) (2,3)
C) (-2,2)
D) (2,-2)

Answers

Answer:

A) (3, 2)

Step-by-step explanation:

y = 4x - 10

y = 2

Substitute y with 2 in the first equation and solve for x.

y = 4x - 10

2 = 4x - 10

12 = 4x

3 = x

Solution: x = 3, y = 2

Answer: A) (3, 2)

Em uma prova de conhecimentos gerais, Fernando errou 3/8 do total de 72 questões. Quantas são as questões que Fernando ACERTOU?

Answers

Vamos lá.....

Duas maneiras praticas:

1 - Multiplicar a fraçao pelo total, vai informar quanto a fracao representa (o que é questionado na questao)

2 - Regra de 3.

1:

72 × (3/8)

216/8

27

Ele acertou 27 questoes

(pergunta mais que interessante: qntas questoes havia na prova??? 72)

which is true about the solution to the system of inequalities shown?

A) y ≥ 1/3x + 3 AND 3x - y > 2

B) y ≥ 1/2x + 3 AND 3x - y > 2

C) y ≥ 1/3x + 3 AND 3x + y > 2

D) y ≥ 1/3x + 3 AND 2x - y > 2

Answers

Answer:

the solution to the system of inequality is C

Help ASAP!!!

Identify the correct trigonometry formula to use to solve for x.

Answers

Answer:

The answer is option 2.

Step-by-step explanation:

You have to apply Cosine Rule, cosθ = adjacent/hypotenuse. Then, you have to substitute the values into the formula :

[tex]cos(θ) = \frac{adj.}{hypo.} [/tex]

[tex]let \: θ = 55[/tex]

[tex]let \: adj. = 11[/tex]

[tex]let \: hypo. = x[/tex]

[tex]cos(55) = \frac{11}{x} [/tex]

The correct trigonometry formula to use to solve for x is [tex]\frac{11}{x}[/tex] . Thus option 1 is correct.

According to the question, we have

base = 11

hypotenuse = x

here for [tex]cos Ф[/tex]Ф,  it is not required to find the value of perpendicular,

we know that in a right-angle triangle using trigonometric ratio, we get

[tex]cos Ф[/tex] Ф = [tex]\frac{base }{hypotenuse}[/tex]

[tex]cos Ф[/tex] Ф = [tex]\frac{11}{x}[/tex]  

here  Ф = [tex]55 ^0[/tex]

[tex]cos 55^o = \frac{11}{x}[/tex]

Thus, the value of the trigonometry formula to use to solve for x is  [tex]\frac{11}{x}[/tex].

Thus option 1 is correct.

Learn more about Trigonometry here :

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Compute the mean and variance of the following probability distribution. (Round your answers to 2 decimal places.) x P(x) 6 0.10 12 0.35 18 0.25 24 0.30

Answers

Answer:

Mean = 16.5

Variance = 35.55

Step-by-step explanation:

           x      P(x)        x. P(x)     x²            x². P(x)

          6      0.10          0.6      36            3.6

         12     0.35          4.2       144           50.4

        18     0.25           4.5       324            81

        24     0.30          7.2        576         172.8

                  ∑x P (x)  16.5         ∑x² P (x) 307.8

The expected value of x E[X] gives the mean where X is the discrete random variable with the given probabilities.

Mean is given by  E(X)=  ∑x P (x) =  16.5

Similarly the variance is also calculated using the expected value of X and X².

Variance is given= E(X)²-  [E(X)]²= 307.8- (16.5)²=  307.8-272.25 = 35.55

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