[tex]\dfrac{x}{5}=-2\\\\x=-10[/tex]
Answer:
[tex]\huge \boxed{{x=-10}}[/tex]
Step-by-step explanation:
[tex]\displaystyle \frac{x}{5} =-2[/tex]
We need the x variable to be isolated on one side of the equation, so we can find the value of x.
Multiply both sides of the equation by 5.
[tex]\displaystyle \frac{x}{5}(5) =-2(5)[/tex]
Simplify the equation.
[tex]x=-10[/tex]
The value of x that makes the equation true is -10.
Question 1: A triangle has sides with lengths 5, 6, and 7. Is the triangle right, acute, or obtuse?
A)Right
B)Obtuse
C)Can't be determined
D) Acute
Question 2: A 15-foot statue casts a 20-foot shadow. How tall is a person who casts a 4-foot-long shadow?
A)0.33 feet
B)3.75 feet
C)3 feet
D)5 feet
Question 3: A triangle has sides with lengths 17, 12, and 9. Is the triangle right, acute, or obtuse?
A)Acute
B)Right
C)Can't be determined
D)Obtuse
Question 4: Two friends are standing at opposite corners of a rectangular courtyard. The dimensions of the courtyard are 12 ft. by 25 ft. How far apart are the friends?
A)21.34 ft.
B)21.93 ft.
C)27.73 ft.
D)19.21 ft.
Answer:
Question 1 = D) Acute
Question 2 = C)3 feet
Question 3 = D) Obtuse
Question 4 = C)27.73 ft.
Step-by-step explanation:
Question 1: A triangle has sides with lengths 5, 6, and 7. Is the triangle right, acute, or obtuse?
In order to be able to accurately classify that a triangle with 3 given sides is either a right , acute or obtuse angle, we use the Pythagoras Theorem
Where:
If a² + b² = c² = Right angle triangle
If a² +b² > c² = Acute triangle.
If a² +b² < c² = Obtuse triangle.
It is important to note that the length ‘‘c′′ is always the longest.
Therefore, for the above question, we have lengths
5 = a, 6 = b and c = 7
a² + b² = c²
5² + 6² = 7²
25 + 36 = 49
61 = 49
61 ≠ 49, Hence 61 > 49
Therefore, this is an Acute Triangle
Question 2: A 15-foot statue casts a 20-foot shadow. How tall is a person who casts a 4-foot-long shadow?
This is question that deals with proportion.
The formula to solve for this:
Height of the statue/ Length of the shadow of the person = Height of the person/ Length of the shadow of the person
Height of the statue = 15 feet
Length of the shadow of the person = 20 feet
Height of the person = unknown
Length of the shadow of the person = 4
15/ 20 = Height of the person/4
Cross Multiply
15 × 4 = 20 × Height of the person
Height of the person = 15 × 4/20
= 60/20
Height of the person = 3 feet
Therefore, the person is 3 feet tall.
Question 3: A triangle has sides with lengths 17, 12, and 9. Is the triangle right, acute, or obtuse?
In order to be able to accurately classify that a triangle with 3 given sides is either a right , acute or obtuse angle, we use the Pythagoras Theorem
Where:
If a² + b² = c² = Right angle triangle
If a² +b² > c² = Acute triangle.
If a² +b² < c² = Obtuse triangle.
It is important to note that the length ‘‘c′′ is always the longest.
Therefore, for the above question, we have lengths 17, 12, 9
9 = a, 12 = b and c = 17
a² + b² = c²
9² + 12² = 17²
81 + 144 = 289
225 = 289
225 ≠ 289
225 < 289
Hence, This is an Obtuse Triangle.
Question 4: Two friends are standing at opposite corners of a rectangular courtyard. The dimensions of the courtyard are 12 ft. by 25 ft. How far apart are the friends?
To calculate how far apart the two friends are we use the formula
Distance = √ ( Length² + Breadth²)
We are given dimensions: 12ft by 25ft
Length = 12ft
Breadth = 25ft
Distance = √(12ft)² + (25ft)²
Distance = √144ft²+ 625ft²
Distance = √769ft²
Distance = 27.730849248ft
Approximately ≈27.73ft
Therefore, the friends are 27.73ft apart.
Volume 1 (3)3 = 367
SSCE/JME-TYPE OF
2
The area of an equilateral triangle of side 8 cm is
A. 16V3 cm? B. 32/3 cm
B.
48 cm
cm?
D.
36V3 cm
A
parallelogram
of area 425 cmhas a height o
Answer:
[tex]A.\ 16\sqrt3\ cm^2[/tex] is the correct answer.
Step-by-step explanation:
Given that:
Side of an equilateral triangle = 8 cm
To find:
Area of the triangle will be:
[tex]A.\ 16\sqrt3\ cm^2[/tex]
[tex]B.\ \dfrac{32}{3} cm^2[/tex]
[tex]C.\ 48\ cm^2[/tex]
[tex]D.\ 36\sqrt3\ cm^2[/tex]
Solution:
First of all, let us have a look at the formula for area of an equilateral triangle:
[tex]A =\dfrac{\sqrt3}{4}a^2[/tex]
Where [tex]a[/tex] is the side of equilateral triangle and an equilateral triangle is a closed 3 sided structure in 2 dimensions which has all 3 sides equal to each other.
Here, we are given that side, [tex]a=8\ cm[/tex]
Putting the value in formula:
[tex]A =\dfrac{\sqrt3}{4}\times 8^2\\\Rightarrow A =\dfrac{\sqrt3}{4}\times 64\\\Rightarrow A =\sqrt3\times 16\\OR\\\Rightarrow \bold{A =16\sqrt3\ cm^2}[/tex]
Hence, [tex]A.\ 16\sqrt3\ cm^2[/tex] is the correct answer.
Find the center, vertices, and foci of the ellipse with equation 4x2 + 9y2 = 36. Center: (0, 0); Vertices: (-3, 0), (3, 0); Foci: Ordered pair negative square root 5 comma 0 and ordered pair square root 5 comma 0 Center: (0, 0); Vertices: (-9, 0), (9, 0); Foci: Ordered pair negative square root 65 comma 0 and ordered pair square root 65 comma 0 Center: (0, 0); Vertices: (0, -3), (0, -3); Foci: Ordered pair 0 comma negative square root 5 and ordered pair 0 comma square root 5 Center: (0, 0); Vertices: (0, -9), (0, 9); Foci: Ordered pair 0 comma negative square root 65 and ordered pair 0 comma square root 65
Answer:
Option A.
Step-by-step explanation:
The given equation of ellipse is
[tex]4x^2+9y^2=36[/tex]
Divide both sides by 36.
[tex]\dfrac{4x^2}{36}+\dfrac{9y^2}{36}=1[/tex]
[tex]\dfrac{x^2}{9}+\dfrac{y^2}{4}=1[/tex]
[tex]\dfrac{x^2}{3^2}+\dfrac{y^2}{2^2}=1[/tex] ...(1)
The standard form of an ellipse is
[tex]\dfrac{(x-h)^2}{a^2}+\dfrac{(y-k)^2}{b^2}=1[/tex] ...(2)
where, (h,k) is center, (h±a,k) are vertices and (h±c,k) are foci.
On comparing (1) and (2), we get
[tex]h=0,k=0,a=3,b=2[/tex]
Now,
Center [tex]=(h,k)=(0,0)[/tex]
Vertices [tex]=(h\pm a,k)=(0\pm 3,0)=(3,0),(-3,0)[/tex]
We know that
[tex]c=\sqrt{a^2-b^2}=\sqrt{3^2-2^2}=\sqrt{5}[/tex]
Foci [tex]=(h\pm c,k)=(0\pm \sqrt{5},0)=(\sqrt{5},0),(-\sqrt{5},0)[/tex]
Therefore, the correct option is A.
Justine and Meagan played a trivia game. Justine answered a question incorrectly and lost 7 points. Then Meagan answered correctly and got the opposite score. Which is the correct way to represent that “the opposite of Justine’s score was equal to Meagan’s score
Answer:
[tex]m = -j[/tex], or in this case, [tex]m=-(-7)[/tex]
Step-by-step explanation:
Assuming that Justine's score is represented by [tex]j[/tex] and Meagan's score is represented by [tex]m[/tex], we know that [tex]j[/tex] will always be the opposite of [tex]m[/tex].
To represent opposite, we put a negative sign before the variable.
This makes the current number, even if it's negative, the opposite value.
Let's test it out.
Since Justine's score is -7, substituting it into the equation makes it [tex]m=-(-7)[/tex]. We know that two negatives make a positive, so [tex]m=7[/tex].
Now let's assume Justine's score is 7. Plugging it into the equation, we get [tex]m=-(7)[/tex]. That's the same thing as [tex]m = -1(7)[/tex], and -1 times 7 is -7.
Hope this helped!
A rotating light is located 16 feet from a wall. The light completes one rotation every 2 seconds. Find the rate at which the light projected onto the wall is moving along the wall when the light's angle is 20 degrees from perpendicular to the wall.
Answer:
a
Step-by-step explanation:
answer is a on edg
Please help!!! A calculator was used to perform a linear regression on the values in the table. The results are shown to the right of the table.What is the line of best fit?A.y = –0.984x + 13.5B.y = –2.9x + 13.5C.–0.984 = –2.9x + 13.5D.y = 13.5x – 2.9
Answer:
B.y = –2.9x + 13.5 i think dont word me for it
Step-by-step explanation:
Equation of line is y = –2.9x + 13.5 which is correct option(B).
What is linear equation?A linear equation is defined as an equation in which the highest power of the variable is always one.
Let y = a + bx, where a is the y-intercept and b is the slope.
[tex]\sum{x} = 1 + 2 + 3 + 4 + 5 = 15[/tex]
[tex]\sum{y} = 11 + 8 + 4+ 1 + 0 = 24[/tex]
[tex]\sum {xy} = 11 + 16 + 12 + 4 + 0 = 43[/tex]
[tex]\sum{x^2} = 1 + 4 + 9 + 16 + 25 = 55[/tex]
[tex]n = 5[/tex]
[tex]b= \dfrac{n\sum{xy}-\sum{x}\sum{y}}{n{\sum{x^2}-(\sum{x}})^2}[/tex]
[tex]b= \dfrac{ 5 (43) - (15) . (24)}{{5 (55) - (15})^2}[/tex]
[tex]b= -2.9[/tex]
[tex]a = \dfrac{25}{5} - (-2.9)\dfrac{15}{5}[/tex]
[tex]a=13.5[/tex]
Hence, equation of line is y = –2.9x + 13.5
Learn more about linear equation here:
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800,000+700 standard form
Answer:
800700
Step-by-step explanation:
800000 + 00000 + 0000 + 000 + 00 + 0
000000 + 00000 + 0000 + 700 + 00 + 0
------------------------------------------------------------
= 800700
Answer:
Hey there!
800000+700=800700
Hope this helps :)
By using words per sentence and characters per words, we can create formulas for the Flesch-Kincaid grade level readability. The readability statistics for random pages from a Harry Potter novel are given below.
Words/Sentence 15.7 9 16.3 14.5 9.7 7.4 14 16.1 13.9 12.5 17.2 11.5
Characters/Word 41 4.2 4.2 4.3 4.3 4.2 4.5 4.5 4.3 4 4.4 4.3
F-K Grade Level 5.2 3.7 6.1 4.9 4.4 3.2 5.6 6.9 5.7 4.1 6.7 4.4
What is the correct analysis statement for the coefficient of determination between words per sentence (x-variable) and characters per word (y-variable)?
a. 1.5% of the variance in characters per word is accounted for by words per sentence.
b. 8% of the variance in characters per word is accounted for by words per sentence.
c. 10% of the variance in characters per word is accounted for by words per sentence.
d. 31% of the variance in characters per word is accounted for by words per sentence.
e. None of these
Answer:
d. 31% of the variance in characters per word is accounted for by words per sentence.
Step-by-step explanation:
The coefficient of determination is the statistical measurement that determines the impact in difference of one variable which is explained by the difference in another variable. It is denoted by [tex]R^{2}[/tex] or R-squared. It helps in predicting the outcome of the event.
Complete the square: x2+7x+?=(x+?)2
Answer:
x² + 7x + 49/4 = (x + 7/2)²
Step-by-step explanation:
x² + bx + c is a perfect square when c = (b/2)².
b = 7, c = (7/2)² = 49/4.
x² + 7x + 49/4 = (x + 7/2)²
Answer:
x² + 7x + 12.25 = (x+3.5)²
Step-by-step explanation:
(a+b)² = a²+ 2ab + b²
then:
7x = 2ab
7/2 = 3.5
then:
(x+3.5)² = x² + 2*3.5*a + 3.5²
x² + 7x + 12.25 = (x+3.5)²
solve the following inequalities 7 x minus 5 / 8 x + 3 >4
Answer:
[tex]x> \frac{8}{51} [/tex]
Step-by-step explanation:
[tex]7x - \frac{5}{8} x + 3>4[/tex]
Bring constants to one side, simplify:
[tex] \frac{51}{8} x>4 - 3 \\ \frac{51}{8} x>1 \\ x>1 \div \frac{51}{8} \\ x>1 \times \frac{8}{51} \\ x> \frac{8}{51} [/tex]
*Note that the inequality sign only changes when you divide the whole inequality by a negative number.
Answer:
[tex]x>\frac{8}{51}[/tex]
Step-by-step explanation:
[tex]7x-\frac{5}{8}x+3>4\\\mathrm{Subtract\:}3\mathrm{\:from\:both\:sides}\\7x-\frac{5}{8}x+3-3>4-3\\\mathrm{Simplify}\\7x-\frac{5}{8}x>1\\\mathrm{Multiply\:both\:sides\:by\:}8\\7x\times \:8-\frac{5}{8}x\times \:8>1\times \:8\\\mathrm{Simplify}\\56x-5x>8\\51x>8\\\mathrm{Divide\:both\:sides\:by\:}51\\\frac{51x}{51}>\frac{8}{51}\\\\x>\frac{8}{51}[/tex]
I hope it helps :)
Which is the ratio of the number of months that begin with the letter M to the total number of months in a year? 2 to 12 2 to 10 10 to 12 12 to 2
Answer:
the answer will be 2 to 12
Answer:
2 to 12
Step-by-step explanation:
just did a quiz got it right
In the diagram, ∆ABC and ∆DBE are similar. What is the scale factor of the dilation that will map the preimage ΔABC onto the image ΔDBE? A. 1.33 B. 0.75 C. 0.66 D. 0.55
Answer:
B
Step-by-step explanation:
Calculate the ratio of corresponding sides, image to preimage, that is
scale factor = [tex]\frac{DE}{AC}[/tex] = [tex]\frac{12.09}{16.12}[/tex] = 0.75 → B
The scale factor of the dilation will be 1.33. Then the correct option is A.
What is dilation?Dilation is the process of increasing the size of an item without affecting its form. Depending on the scale factor, the object's size can be raised or lowered.
There is no effect of dilation on the angle.
In the diagram, ∆ABC and ∆DBE are similar.
Then the scale factor of the dilation that will map the preimage ΔABC onto the image ΔDBE will be
⇒ 16.12 / 12.09
⇒ 1.33
Then the correct option is A.
More about the dilation link is given below.
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Which system of linear inequalities has the point (3, –2) in its solution set?
Answer:
see below
Step-by-step explanation:
We want where both inequalities are true
y > -3
-2 >-3 this is true
y ≥ 2/3x -4
-2≥ 2/3*3 -4
-2 ≥ 2 -4
-2≥ -2
This is true
This is is the graph
Answer:
[tex]\boxed{\sf Option \ 3}[/tex]
Step-by-step explanation:
[tex]\sf The \ values \ must \ be \ true \ for \ both \ inequalities.[/tex]
[tex]x = 3\\y = -2[/tex]
[tex]y>-3\\-2>-3\\ \sf True[/tex]
[tex]y\geq \frac{2}{3}x-4 \\ -2\geq \frac{2}{3}(3)-4\\2\geq 2-4\\-2\geq-2 \\ \sf True[/tex]
Find the interquartile range of the following data set. Number of Points Scored at Ten Basketball Games 57 63 44 29 36 62 48 50 42 34 A.21 B.28 C.6 D.34
Answer:
total number(n)=10
divided the total number into two equal parts so
in one group of number =5
ln first phase group of number middle value =44
In second phase group of number middle value=50
then using formula,q1=44 q3=50
inter quartile range =q3_q1
=50-44
=6
therefore interquartile range =6
Answer: The answer is 6
Simplify the expression. Write the answer using scientific notation.
(5x107)(6x104)
A) 1.1 x 1012
B) 3.0x 1029
C) 3.0 x 1012
D) 1.1 x 1029
Answer:
3* 10 ^12
Step-by-step explanation:
(5x10^7)(6x10^4)
Multiply the numbers together
5*6 =30
Add the exponents
10^7 * 10 ^ 4 = 10 ^(7+4) = 10 ^11
30 * 10 ^11
But this is not scientific notation since 30 >10
Move the decimal one place to the left and add 1 to the exponent
3* 10 ^12
Answer:
3* 10 ^12
Step-by-step explanation:
In the expression 3x2 + y − 5, which of the following choices is the exponent in the term 3x2?
Answer:
2
Step-by-step explanation:
The term 3x² has 2 as an exponent, the correct option is C.
What are Exponents?Exponents are the base raised by power, it is written in the superscript of a number.
The expression is 3x² +y-5
The term 3x² has 2 as an exponent.
Therefore, the correct option is C.
The missing options are
A.3x2
B. y
A 2
C. -5
D. None of these choices are correct.
To know more about Exponents
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33 points
1. A sandwich vendor offers a choice of hamburger, chicken, or fish on
either a plain or sesame seed bun. How many different types of
sandwiches are there to choose from?
*
4
6
12
3
Answer:
6 sandwiches to choose from because
3×2 = 6
For a trip, Eli packed 3 shirts, 3 pairs of pants, and 2 pairs of shoes. How many different outfits can Eli make? A. 6 outfits B. 8 outfits C. 9 outfits D. 18 outfits Please include ALL work!
Answer:
18 outfits
Step-by-step explanation:
To determine the number of outfits available
3 shirts * 3 pairs of pants * 2 pairs of shoes
3*3*2
18
After basketball practice, Courtney spent extra time working on free throws. Overall, she made 3 of her 5 shots. What percent of her total shots did she make?
Answer:
I know the answer
Step-by-step explanation:
Courtney made 60% of her shots
Answer:
she made a 60%
Step-by-step explanation:
first you do this 3÷5
that gives you .60
inorder to get a percent multiply by 100
that gives you an end result of 60
add the percent sing and your done 60%
hope i helped
Please! David has several chains of length 5 and of length 7. By joining chains one after the other, David can create different lengths. Which of these lengths is impossible to make? A)10 B)12 C)13 D)14 E)15
Answer:
13
Step-by-step explanation:
A)5+5=10
B)5+7=12
C) impossible
D)7+7=14
E)5+5+5=15
(05.06A LC)
Line segment AB has a length of 4 units. It is translated 1 unit to the right on a coordinate plane to obtain line segment A'B'. What is the length
of A'B'?
1 unit
4 units
5 units
6 units
Answer:
4 units
Step-by-step explanation:
A transformation is the movement of a point from one position to another position. If a shape is transformed all its points are also transformed. Types of transformations are translation, rotation, reflection and dilation.
If a shape is transformed, the length of its sides and shape remains the same, only the position changes.
If Line segment AB has a length of 4 units. It is translated 1 unit to the right on a coordinate plane to obtain line segment A'B, the length of A'B' remains the same which is 4 unit. To prove this:
Let A be at ([tex]x_1,y_1[/tex]) and B be at ([tex]x_2,y_2[/tex]). The length of AB is:
[tex]AB=\sqrt{(y_2-y_1)^2+(x_2-x_1)^2}[/tex]
If AB is translated to the right by 1 unit the new points are A' at ([tex]x_1+1,y_1[/tex]) and B' at ([tex]x_2+1,y_2[/tex]). The length of A'B' is:
[tex]A'B'=\sqrt{(y_2-y_1)^2+(x_2+1-(x_1+1))^2}=\sqrt{(y_2-y_1)^2+(x_2+1-x_1-1)^2}\\\\A'B'=\sqrt{(y_2-y_1)^2+(x_2-x_1)^2}[/tex]
AB = A'B' = 4 units
could I please have some help
For the equation ax+c =bx +d where a≠b and c≠d , what is x expressed in terms of a,b,c, and d?
Answer:
x = (d - c) / (a - b)
Step-by-step explanation:
Let's simply isolate and solve for the variable x.
ax + c = bx + d
ax - bx + c = d
x (a - b) = d - c
x = (d - c) / (a - b)
Thus, we have expressed x in terms of a,b,c, and d.
Cheers.
:)
The value of x in terms of a,b,c, and d will be x = (d - c) / (a - b).
What is an arithmetic operation?It is described as the process through which we add, subtract, multiply, and divide numerical values. It has the fundamental operators +, -, ×, and ÷.
The order in which arithmetic operations must be performed in an equation is referred to as PEMDAS. This rule states that operations must be performed as follows: parentheses, exponents, multiplication, or division, followed by addition or subtraction.
It is given that,
ax+c =bx +d
a≠b and c≠d
Rearrange the equation and solve it for the x in the following steps,
ax - bx + c = d
x (a - b) = d - c
x = (d - c) / (a - b)
Thus,the value of x in terms of a,b,c, and d will be x = (d - c) / (a - b).
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A controversial bill is being debated in the state legislature. Representative Williams wants to estimate within 2 percentage points and with 95% confidence the difference in the proportion of her male and female constituents who favor the bill. What sample size should she obtain?
Answer:
The sample size is [tex]n = 2401[/tex]
Step-by-step explanation:
From the question we are told that
The margin of error is [tex]E= 2\% = 0.02[/tex]
Given that the confidence level is 95% then the level of significance is mathematically evaluated as
[tex]\alpha = (100 - 95)\%[/tex]
[tex]\alpha = 5\% = 0.05[/tex]
The critical value of [tex]\frac{\alpha }{2}[/tex] obtained from the normal distribution table is [tex]Z_{\frac{\alpha }{2} } = 1.96[/tex]
Let assume that the sample proportion is [tex]\r p = 0.5[/tex]
Generally the sample size is evaluated as
[tex]n = [\frac{Z_{\frac{\alpha }{2} }}{E} ]^2 * \r p ( 1- \r p )[/tex]
[tex]n = [\frac{1.96}{0.02} ]^2 * 0.5 ( 1- 0.5 )[/tex]
[tex]n = 2401[/tex]
do numbers ever stop
Nope, i dont think so
Answer:
no the numbers are infinite
Step-by-step explanation:
Can your help me please?
Answer:
(-5, 0) and (0,4)
Step-by-step explanation:
Given equation: -4x + 5y = 20
Sub. in the values
When x = -5 and y = 0 (-5,0),
[tex] - 4( - 5) + 5(0) = 20 [/tex]
When x = 0 and y = 4 (0,4),
[tex] - 4(0) + 5(4) = 20[/tex]
That's how I would do it, not sure if your school has another method. Hope this helps :)
Answer: x = -5 and y = 4
Step-by-step explanation: its the first option do you need me to exlain how cuz its multiple choice
Can you wiggle your ears? Use the students in your statistics class (or a group of friends) to estimate the percentage of people who can wiggle their ears. How can your result be thought of as an estimate for the probability that a person chosen at random can wiggle his or her ears? Comment: National statistics indicate that about 13% of Americans can wiggle their ears (Source: Bernice Kanner, Are You Normal?, St. Martin's Press, New York). The resulting relative frequency can be used as an estimate of the true probability of all Americans who can wiggle their ears. The resulting relative frequency can be used as an estimate of the true probability of all Americans who cannot wiggle their ears. The resulting relative frequency is the true probability of all Americans who can wiggle their ears. The resulting relative frequency cannot be used as an estimate of the true probability of all Americans who can wiggle their ears.
Answer:36
Step-by-step explanation:
Vu is three times as old as Wu. In 25 years Wu will be twice as old as Vu. How old is Vu now?
Answer: Vu is 15 years old now.
Step-by-step explanation:
Let present age of WU be x.
Then, the present age of Vu = 3x
Also, After 25 years
Age of Wu = x+25
According to the question:
[tex](x+25)=2(3x)\\\\\Rightarrow\ x+25=6x\\\\\Rightarrow\5x=25\\\\\Rightarrow\ x=5[/tex]
Present age of Vu = 3(5) = 15
Hence, Vu is 15 years old now.
Answer:
j
Step-by-step explanation:j
A scatter plot is shown below.. PLEASE HELPPP!!
Answer:
(0,9.8) and (10, 1.2)
Step-by-step explanation:
These are the only points that are the best fit for the garph correlation.
Answer:
(0, 9.8) and (10, 1.2)
Step-by-step explanation:
:) hope this helped
The heat evolved in calories per gram of a cement mixture is approximately normally distributed. The mean is thought to be 100, and the standard deviation is 2. You wish to test H0: μ = 100 versus H1: μ ≠ 100 with a sample of n = 9 specimens.
A. If the acceptance region is defined as 98.5 le x- 101.5, find the type I error probability alpha.
B. Find beta for the case where the true mean heat evolved is 103.
C. Find beta for the case where the true mean heat evolved is 105. This value of beta is smaller than the one found in part (b) above. Why?
Answer:
A.the type 1 error probability is [tex]\mathbf{\alpha = 0.0244 }[/tex]
B. β = 0.0122
C. β = 0.0000
Step-by-step explanation:
Given that:
Mean = 100
standard deviation = 2
sample size = 9
The null and the alternative hypothesis can be computed as follows:
[tex]\mathtt{H_o: \mu = 100}[/tex]
[tex]\mathtt{H_1: \mu \neq 100}[/tex]
A. If the acceptance region is defined as [tex]98.5 < \overline x > 101.5[/tex] , find the type I error probability [tex]\alpha[/tex] .
Assuming the critical region lies within [tex]\overline x < 98.5[/tex] or [tex]\overline x > 101.5[/tex], for a type 1 error to take place, then the sample average x will be within the critical region when the true mean heat evolved is [tex]\mu = 100[/tex]
∴
[tex]\mathtt{\alpha = P( type \ 1 \ error ) = P( reject \ H_o)}[/tex]
[tex]\mathtt{\alpha = P( \overline x < 98.5 ) + P( \overline x > 101.5 )}[/tex]
when [tex]\mu = 100[/tex]
[tex]\mathtt{\alpha = P \begin {pmatrix} \dfrac{\overline X - \mu}{\dfrac{\sigma}{\sqrt{n}}} < \dfrac{\overline 98.5 - 100}{\dfrac{2}{\sqrt{9}}} \end {pmatrix} + \begin {pmatrix}P(\dfrac{\overline X - \mu}{\dfrac{\sigma}{\sqrt{n}}} > \dfrac{101.5 - 100}{\dfrac{2}{\sqrt{9}}} \end {pmatrix} }[/tex]
[tex]\mathtt{\alpha = P ( Z < \dfrac{-1.5}{\dfrac{2}{3}} ) + P(Z > \dfrac{1.5}{\dfrac{2}{3}}) }[/tex]
[tex]\mathtt{\alpha = P ( Z <-2.25 ) + P(Z > 2.25) }[/tex]
[tex]\mathtt{\alpha = P ( Z <-2.25 ) +( 1- P(Z < 2.25) })[/tex]
From the standard normal distribution tables
[tex]\mathtt{\alpha = 0.0122+( 1- 0.9878) })[/tex]
[tex]\mathtt{\alpha = 0.0122+( 0.0122) })[/tex]
[tex]\mathbf{\alpha = 0.0244 }[/tex]
Thus, the type 1 error probability is [tex]\mathbf{\alpha = 0.0244 }[/tex]
B. Find beta for the case where the true mean heat evolved is 103.
The probability of type II error is represented by β. Type II error implies that we fail to reject null hypothesis [tex]\mathtt{H_o}[/tex]
Thus;
β = P( type II error) - P( fail to reject [tex]\mathtt{H_o}[/tex] )
∴
[tex]\mathtt{\beta = P(98.5 \leq \overline x \leq 101.5) }[/tex]
Given that [tex]\mu = 103[/tex]
[tex]\mathtt{\beta = P( \dfrac{98.5 -103}{\dfrac{2}{\sqrt{9}}} \leq \dfrac{\overline X - \mu}{\dfrac{\sigma}{n}} \leq \dfrac{101.5-103}{\dfrac{2}{\sqrt{9}}}) }[/tex]
[tex]\mathtt{\beta = P( \dfrac{-4.5}{\dfrac{2}{3}} \leq Z \leq \dfrac{-1.5}{\dfrac{2}{3}}) }[/tex]
[tex]\mathtt{\beta = P(-6.75 \leq Z \leq -2.25) }[/tex]
[tex]\mathtt{\beta = P(z< -2.25) - P(z < -6.75 )}[/tex]
From standard normal distribution table
β = 0.0122 - 0.0000
β = 0.0122
C. Find beta for the case where the true mean heat evolved is 105. This value of beta is smaller than the one found in part (b) above. Why?
[tex]\mathtt{\beta = P(98.5 \leq \overline x \leq 101.5) }[/tex]
Given that [tex]\mu = 105[/tex]
[tex]\mathtt{\beta = P( \dfrac{98.5 -105}{\dfrac{2}{\sqrt{9}}} \leq \dfrac{\overline X - \mu}{\dfrac{\sigma}{n}} \leq \dfrac{101.5-105}{\dfrac{2}{\sqrt{9}}}) }[/tex]
[tex]\mathtt{\beta = P( \dfrac{-6.5}{\dfrac{2}{3}} \leq Z \leq \dfrac{-3.5}{\dfrac{2}{3}}) }[/tex]
[tex]\mathtt{\beta = P(-9.75 \leq Z \leq -5.25) }[/tex]
[tex]\mathtt{\beta = P(z< -5.25) - P(z < -9.75 )}[/tex]
From standard normal distribution table
β = 0.0000 - 0.0000
β = 0.0000
The reason why the value of beta is smaller here is that since the difference between the value for the true mean and the hypothesized value increases, the probability of type II error decreases.
