Answer:
[tex] \frac{1}{9 - 4i} [/tex]
I'm not sure
Simplify the expression 4x^3 2x^3
Answer:
Step-by-step explanation:
2 3x6
the 3 is an exponet so supost to be smaller
the answer- 2^3 x^6
i think its right
x⁴+1/x⁴=47,find the value of x³+1/x³
Answer:
The value of x^3 + 1/x^3 is 47/x + 1/x^3 - 1/x^5
Step-by-step explanation:
x^4 + 1/x^4 = 47
x^4 = 47 - 1/x^4
x^3 + 1/x^3 = 1/x(x^4 + 1/x^2)
x^4 = 47 - 1/x^4
x^3 + 1/x^3 = 1/x(47 - 1/x^4 + 1/x^2) = 47/x - 1/x^5 + 1/x^3 = 47/x + 1/x^3 - 1/x^5
A digital scale measures weight to the nearest 0.2 pound. Which measurements shows an appropriate level for the scale ?
Answer: Answer choices 1, 3, 4
Step-by-step explanation:
As long as it ends in .0, .2, .4, .6, or .8 it's fine. Therefore the first and last 2 work, since 0.2 can end in either of those 5 values.
Hope that helped,
-sirswagger21
Solve x2 - 4x - 7 = 0 by completing the square. What are the solutions?
Answer:
[tex]x=2+\sqrt{11},\:x=2-\sqrt{11}[/tex]
Step-by-step explanation:
[tex]x^2-4x-7=0\\\mathrm{Solve\:with\:the\:quadratic\:formula}\\Quadratic\:Equation\:Formula\\\mathrm{For\:a\:quadratic\:equation\:of\:the\:form\:}ax^2+bx+c=0\mathrm{\:the\:solutions\:are\:}\\x_{1,\:2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}\\\mathrm{For\:}\quad a=1,\:b=-4,\:c=-7:\quad x_{1,\:2}=\frac{-\left(-4\right)\pm \sqrt{\left(-4\right)^2-4\cdot \:1\left(-7\right)}}{2\cdot \:1}\\x=\frac{-\left(-4\right)+\sqrt{\left(-4\right)^2-4\cdot \:1\left(-7\right)}}{2\cdot \:1}:\quad 2+\sqrt{11}[/tex]
[tex]x=\frac{-\left(-4\right)-\sqrt{\left(-4\right)^2-4\cdot \:1\left(-7\right)}}{2\cdot \:1}:\quad 2-\sqrt{11}\\\mathrm{The\:solutions\:to\:the\:quadratic\:equation\:are:}\\x=2+\sqrt{11},\:x=2-\sqrt{11}[/tex]
1960 were polled. 279 of them preferred Rock and Roll. What is the % of these students?
Answer:
14.2% students
Step-by-step explanation:
279 / 1960 = 0.142
0.142 x 100% = 14.2 %
CAN SOMEONE HELP ME IN THIS INTEGRAND QUESTION PLS PLS PLS PLS
''Find the surface area between the z = 1 and z = 4 planes of z = x ^ 2 + y ^ 2 paraboloid.''
Answer:
Step-by-step explanation:
Answer:
S = ⅙ π (65^³/₂ − 5^³/₂)
Step-by-step explanation:
z = x² + y², 1 < z < 4
Surface area is:
S = ∫∫√(1 + (fₓ)² + (fᵧ)²) dA
where fₓ and fᵧ are the partial derivatives of f(x,y) with respect to x and y, respectively.
fₓ = 2x, fᵧ = 2y
S = ∫∫√(1 + (2x)² + (2y)²) dA
S = ∫∫√(1 + 4x² + 4y²) dA
For ease, convert to polar coordinates.
S = ∫∫√(1 + 4r²) dA
S = ∫∫√(1 + 4r²) r dr dθ
At z = 1, r = 1. At z = 4, r = 4.
So 1 < r < 4, and 0 < θ < 2π. These are the limits of the integral.
S = ∫₀²ᵖⁱ∫₁⁴√(1 + 4r²) r dr dθ
To integrate, use u-substitution.
u = 1 + 4r²
du = 8r dr
⅛ du = r dr
When r = 1, u = 5. When r = 4, u = 65.
S = ∫₀²ᵖⁱ∫₅⁶⁵√u (⅛ du) dθ
S = ∫₀²ᵖⁱ (⅛ ∫₅⁶⁵√u du) dθ
S = ∫₀²ᵖⁱ (¹/₁₂ u^³/₂ |₅⁶⁵) dθ
S = ∫₀²ᵖⁱ (¹/₁₂ (65^³/₂ − 5^³/₂)) dθ
S = (¹/₁₂ (65^³/₂ − 5^³/₂)) θ |₀²ᵖⁱ
S = (¹/₁₂ (65^³/₂ − 5^³/₂)) (2π)
S = ⅙ π (65^³/₂ − 5^³/₂)
HELP PLEASE!!!!!!!!
Answer:
3¹²
Step-by-step explanation:
Move 3⁻² to the numerator using the negative exponent rule
1/b-n = bⁿ
(3⁵)² ⋅ 3²
Multiply the exponents
3¹⁰ · 3²
Multiply by adding the exponents
3¹⁰⋅ 3²
3¹²
Halle is enteros cuyo producto sea 253 y uno de los enteros debe ser uno más que el doble del otro.
Answer:
11 y 23
Step-by-step explanation:
Nombrando los números como [tex]x[/tex] y [tex]y[/tex],
Planteamos las siguientes ecuaciones:
[tex]xy=253[/tex] (el producto de los numeros es 253)
[tex]x=2y+1[/tex] (uno de los enteros debe ser uno más que el doble del otro).
Sustituimos la segunda ecuación en la primera:
[tex](2y+1)(y)=253[/tex]
resolvemos para encontrar y:
[tex]2y^2+y=253\\2y^2+y-253=0[/tex]
usando la formula general para resolver la ecuación cuadrática:
[tex]y=\frac{-b+-\sqrt{b^2-4ac} }{2a}[/tex]
donde
[tex]a=2,b=1,c=-253[/tex]
Sustituyendo los valores:
[tex]y=\frac{-1+-\sqrt{1-4(2)(-253)} }{2(2)} \\\\y=\frac{-1+-\sqrt{2025} }{4}\\ \\y=\frac{-1+-45}{4} \\[/tex]
usando el signo mas obtenemos que y es:
[tex]y=\frac{-1+45}{4} \\y=\frac{44}{4}\\ y=11[/tex]
(no usamos el signo menos, debido a que obtendriamos fracciones y buscamos numeros enteros)
con este valor de y, podemos encontrar x usando:
[tex]x=2y+1[/tex]
sustituimos [tex]y=11[/tex]
[tex]x=2(11)+1\\x=22+1\\x=23[/tex]
y comprobamos que el producto sea 253:
[tex]xy=253[/tex]
[tex](23)(11)=253[/tex]
Solve for y
A)16
B)18
C)22
D) 30
Omg help me I need help, please help me I’m so nice and funny, I can make u laugh, help me freaks I’m big baller
Answer:
30
Step-by-step explanation:
It is an equalateral triangle
A ball travels on a parabolic path in which the height (in feet) is given by the expression $-25t^2+75t+24$, where $t$ is the time after launch. At what time is the height of the ball at its maximum?
Answer:
The height of the ball is at it's maximum 1.5 units of time after launch.
Step-by-step explanation:
Suppose we have a quadratic function in the following format:
[tex]h(t) = at^{2} + bt + c[/tex]
If t is negative, the maximu value of h(t) will happen at the point
[tex]t_{MAX} = -\frac{b}{2a}[/tex]
In this question:
[tex]h(t) = -25t^{2} + 75t + 24[/tex]
So
[tex]a = -25, b = 75, c = 24[/tex]
Then
[tex]t_{MAX} = -\frac{b}{2a} = -\frac{75}{2*(-25)} = 1.5[/tex]
The height of the ball is at it's maximum 1.5 units of time after launch.
Please answer this correctly
Answer:
Board Games: 30%
Karaoke: 50%
Bowling: 20%
Step-by-step explanation:
Board Games: [tex]\frac{3}{3+5+2} =\frac{3}{10} =\frac{30}{100}[/tex] or 30%
Karaoke: [tex]\frac{5}{3+5+2} =\frac{5}{10} =\frac{50}{100}[/tex] or 50%
Bowling: [tex]\frac{2}{3+5+2} =\frac{2}{10} =\frac{20}{100}[/tex] or 20%
Answer:
Board Games: 30%
Karaoke: 50%
Bowling: 20%
Step-by-step explanation:
3 + 5 + 2 = 10 so there are 10 family members.
3 out of 10 equals 30%
5 out of 10 equals 50%
2 out of 10 equals 20%
Please mark Brainliest if correct
Hope this helps!
2 Ponts
The estimate obtained from a sample of which of the following sizes would
most likely be closest to the actual parameter value of a population?
A. 15
B. 150
C. 75
D. 45
SUBM
Professional basketball coaches may coach at one of three levels: Assistant, Associate, or Head. It is possible to transition from any of these levels (states) to another. Each of these three states is transient because once someone leaves coaching at any level they never return (at least according to our model). On average, annual salary for head coaches is $104,485, for associates is $62,993, and for assistants is $41,389. Using our P matrix, we have solved to find the fundamental matrix (we have called it the (I-Q) inverse matrix): Assist Assoc Head Assist 6 4 2 Assoc 2 6 6 Head 1 2 10 For someone who is a head coach - what is their expected income for the remainder of their professional coaching career?
Answer:
For someone who is a head coach - their expected income for the remainder of their professional coaching career will be
Expected income = 1×$41,389 + 2×$62,993 + 10×$104,485
Expected income = $1,212,225
Step-by-step explanation:
Professional basketball coaches may coach at one of three levels:
AssistantAssociateHeadOn average, the annual salary is given by
Assistant = $41,389Associate = $62,993Head = $104,485Using our P matrix, we have solved to find the fundamental matrix (we have called it the (I-Q) inverse matrix):
Assistant Associate Head
Assistant 6 4 2
Associate 2 6 6
Head 1 2 10
For someone who is a head coach - what is their expected income for the remainder of their professional coaching career?
As per the given P matrix, for someone who is a head coach will be:
Assistant = 1 time
Associate = 2 times
Head = 10 times
Therefore, the expected income will be,
Expected income = 1×$41,389 + 2×$62,993 + 10×$104,485
Expected income = $1,212,225
So, the question is below, please help me find the answer. :)
Answer:
£2.70 fig rolls and £5.72 crisps
Step-by-step explanation:
£1.08+0.54+£1.08= £2.70 fig rolls
£1.43+£1.43+£1.43-£1.43= £2.86 x 2= £5.72 for 6 packets of crisps
£2.70+ £5.72= £8.42
ASAP! GIVING BRAINLIEST! Please read the question THEN answer CORRECTLY! NO guessing. I say no guessing because people usually guess on my questions.
Answer:
C. F(x) = 4x² + 1
Step-by-step explanation:
→The function F(x) shifted 1 unit upwards, meaning there needs to be a 1 being added to the function.
→In addition, the function F(x) has grown narrower, compared to the function G(x). This is from the absolute value of a number being greater than 1, which is being multiplied.
This means the correct answer should be "C. F(x) = 4x² + 1."
In a random sample of six cell phones, the mean full retail price was $538.00 and the standard deviation was $184.00. Assume the population is normally distributed and use the t-distribution to find the margin of error and construct a 90% confidence interval for the population mean mu. Interpret the results. Identify the margin of error. Construct a 90% confidence interval for the population mean. Interpret the results. Select the correct choice below and fill in the answer box to complete your choice.
Answer:
The margin of error is 370.8.
The 90% confidence interval for the population mean is between $167.2 and $908.8
The correct interpretation is that we are 90% sure that the true mean price for all cellphones in within the interval end-points, so option B.
Step-by-step explanation:
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 6 - 1 = 5
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 5 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.0150
The margin of error is:
M = T*s = 2.0150*184 = 370.8.
In which s is the standard deviation of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 538 - 370.8 = $167.2
The upper end of the interval is the sample mean added to M. So it is 538 + 370.8 = $908.8
The 90% confidence interval for the population mean is between $167.2 and $908.8
The correct interpretation is that we are 90% sure that the true mean price for all cellphones in within the interval end-points, so option B.
solve the equation 4x +30 = 2(x-10)
If a man takes 30 minutes to drive at work and it is 44 miles into work what is the average speed?
Answer:
1.46666 miles / minutes
88 miles per hour
Step-by-step explanation:
The speed is distance over time
44 miles / 30 minutes
1.46666 miles / minutes
or if we want in miles per hour
44 miles / .5 hours
88 miles per hour
Answer:
1.467 mile/minute
Step-by-step explanation:
you should divide the distance on the time i.e. 44/30
A local cable company claims that the proportion of people who have Internet access is less than 63%. To test this claim, a random sample of 800 people is taken and its determined that 478 people have Internet access. The following is the setup for this hypothesis test: H0:p=0.63 Ha:p<0.63 Find the p-value for this hypothesis test for a proportion and round your answer to 3 decimal places.
Answer:
Step-by-step explanation:
For the null hypothesis,
H0 : p = 0.63
For the alternative hypothesis,
Ha : p < 0.63
This is a left tailed test
Considering the population proportion, probability of success, p = 0.63
q = probability of failure = 1 - p
q = 1 - 0.63 = 0.37
Considering the sample,
Sample proportion, P = x/n
Where
x = number of success = 478
n = number of samples = 800
P = 478/800 = 0.6
We would determine the test statistic which is the z score
z = (P - p)/√pq/n
z = (0.6 - 0.63)/√(0.63 × 0.37)/800 = - 1.76
From the normal distribution table, the area below the test z score in the left tail 0.039
Thus
p = 0.039
Answer:
-3.66
Step-by-step explanation:
URGENT!! MY LAST 2 QUESTION WILL FOREVER BE GRATEFUL PLS HELP WILL GIVE BRANLIEST!! AT LEAST TAKE A LOOK!!!! PLS I AM BEGGING!!!
13. Assume that you have a square. What can you conclude from applying the law of detachment to this conditional?
If you have a square, then you have a rectangle.
A) You have a quadrilateral.
B) All sides are the same length.
C) Squares and rectangles are the same.
D) You have a rectangle.
14. Which two theorems would justify that m∠4 = m∠6, given that m∠5 = m∠6 in the diagram below?
IMAGE BELOW
A) vertical angles theorem, consecutive interior angles theorem
B) vertical angles theorem, alternate interior angles theorem
C) right angles theorem, exterior angles theorem
D) corresponding angles theorem, angle addition theorem
Answer:
d: please note I am not sure about this but look at my reasoning and maybe you can find your own answer that you are sure about.
D: i am sure about this.
Step-by-step explanation:
From what I looked up, i believe what you are talking about is deductive reasoning, which is based off of facts. It can't be a or b because that wasn't defined in the statement. Squares and rectangles are not the same thing since you can have a square that is a rectangle, but a rectangle that is not a square, so D is correct.
corresponding angles i believe since they are matching
I know that the 2 lines are parallel because 5 and 6 are alternate interior angles since they are on opposite sides.
4 and 6 are not vertical or right angles, so it must be d, also they follow what a corresponding angle is, which is them being matching.
Answer:
13. B
14. D
Step-by-step explanation:
13. Law of Detachment says that if two statements are true then we can derive a third true statement. So, for example, say the first statement is that you are a human. Say the second statement is that you breathe. You can write this as: if you are a human, you breathe. In this case, if you have a square, then you have a rectangle. You have a quadrilateral.
14. 4 and 6 are corresponding angles, since you can tell that there are two parallel lines from angle 5 = angle 6. You can also use angle addition theorem.
–12 + 3b – 1 = –5 – b
Answer:
2
Step-by-step explanation:
-13+3b=-5-b
4b=8
b=2
What’s the correct answer for this question?
Answer:
A.
Step-by-step explanation:
In the attached file
Question 6: An experiment consists of throwing two six-sided dice and observing the number of spots on the upper faces. Determine the probability that (a) each die shows four or more spots. (b) the sum of the spots is not 3. (c) neither a one nor a six appear on each die. (d) the sum of the spots is 7
Answer:
(a) 0.25
(b) 0.944
(c) 0.444
(d) 0.167
Step-by-step explanation:
There are six possible outcomes for each die, which means that the number of possible outcomes is:
[tex]n=6*6 = 36[/tex]
(a) In order for each die to show four or more spots they will both have to land on a four, five or six. The probability of this happening is:
[tex]P(A) = \frac{3*3}{36}=0.25[/tex]
(b) There are only two possible outcomes for which the sum is three (1 and 2, or 2 and 1). The probability of the sum NOT being three is:
[tex]P(B) = 1-\frac{2}{36}=0.944[/tex]
(c) If neither a one or a six must appear, then there are 4 possible outcomes for each die, the probability is:
[tex]P(C) = \frac{4*4}{36}=0.444[/tex]
(d) For each one of the six possible numbers on the first die, there is only one on the second die for which the sum of the spots is 7, totaling six possible ways to sum 7:
[tex]P(D) = \frac{6}{36}=0.167[/tex]
The required probability output from a throw of two six sided dice are as follows :
0.25 0.9440.4440.167The sample space for two throw of a six-sided die :
Sample space = n² = 6² = 6 × 6 = 36Recall :
Probability = required outcome / Total possible outcomesA.) Obtaining 4 or more spots :
Required spot = (5, 6, 7) on each die = 3 × 3 = 9 outcomes
P(4 or more spot) = 9/36 = 0.25
B.) Sum of spot is not 3 :
Sum of spot = 3 ; (1, 2) and (2, 1) = 2 possible outcomes
P(sum not 3) = 1 - (2/36) = 1 - 1/8 = 17/18 = 0.944
C.) neither a one nor 6 appears :
Required = (2, 3, 4, 5) = 4 × 4 = 16
P(neither 6 nor 1) = 16/36 = 4/9 = 0.44
D.) Sum of spot equals 7
Required = (1, 6),(6,1),(5,2),(2,5),(3,4),(4,3) = 6 outcomes
P(sum equals 7) = 6/36 = 1/6 = 0.167
Learn more :https://brainly.com/question/18405415
3 of 6
As an estimation we are told £3 is €4.
Convert £85.40 to euros.
Give your answer rounded to 2 DP
Answer:
€113.67
Step-by-step explanation:
£3 = €4
£85.40 is €x
Cross multiply.
[tex]4 \times 85.4=3x[/tex]
[tex]3x=341.6[/tex]
[tex]\frac{3x}{3}=\frac{341.6}{3}[/tex]
[tex]x=113.86666...[/tex]
Arlinda says there is a linear relationship between the price (p) of 500ml soft drink and the number sold (x). The formula is x = ap + b where a and b are constants. At N$20 she sells 1500 of the 500ml soft drinks but the quantity sold falls by 200 of the 500ml soft drinks when she increases the price by 50%. At what price will 600 of the 500ml energy drinks be sold?
Answer: 600 of the 500ml energy drinks be sold be sold at $45
Step-by-step explanation:
The linear relationship between the price (p) of 500ml soft drink and the number sold (x) is expressed as
x = ap + b
At N$20 she sells 1500 of the 500ml soft drinks. This means that the first equation would be
1500 = 20a + b - - - - - - - - -1
the quantity sold falls by 200 of the 500ml soft drinks when she increases the price by 50%. This means that the new quantity sold is 1500 - 200 = 1300
The price at which they were sold is
20 + (50/100 × 20) = $30
The second equation would be
1300 = 30a + b - - - - - - - - -2
Subtracting equation 2 from equation 1, it becomes
200 = - 10a
a = 200/- 10 = - 20
Substituting a = - 20 into equation 2, it becomes
1300 = 10 × - 20 + b
1300 = - 200 + b
b = 1300 + 200 = 1500
The linear relationship becomes
x = - 20p + 1500
If x = 600, then
600 = - 20p + 1500
- 20p = 600 - 1500 = - 900
p = - 900/ - 20
p = $45
ASAP! GIVING BRAINLIEST! Please read the question THEN answer CORRECTLY! NO guessing. I say no guessing because people usually guess on my questions.
Answer:
B. F(x) = 3(x - 2)² - 2
Step-by-step explanation:
→The function F(x) narrowed, meaning the absolute value being multiplied to the function is greater than 1.
→The function F(x) flipped over the x-axis, this means that the number being multiplied has to be a negative.
→The function F(x) shifted to the left 2 units, this means there needs to be a 2 being added.
→The function F(x) shifted downwards 2 units, meaning there needs to be a 2 being subtracted from the whole function.
This gives us the correct answer of "B. F(x) = 3(x - 2)² - 2."
The yearbook club is handing out T-shirts to its members. There are 5 blue, 7 green, 9 red, and 4 yellow T-shirts in all. If Jacob is handed a T-shirt, what is the probability that the color is red? 925 916 35 1625
Answer:
9/25
Step-by-step explanation:
Don't worry, I just took this test and got it correct. Best of luck to you all!
ASK YOUR TEACHER Two streets meet at an 84° angle. At the corner, a park is being built in the shape of a triangle. Find the area of the park if, along one road, the park measures 190 feet, and along the other road, the park measures 235 feet. (Round your answer to the nearest whole number.)
Answer:
22,203 ft^2
Step-by-step explanation:
The area of a triangle with angle ∅ and two sides a and b is;
Area A = 1/2 × absin∅ ......1
The park is in the shape of a triangle, with two sides and an angle given;
Given;
a = 190 ft
b = 235 ft
∅ = 84°
Substituting the values into equation 1;
Area of the park;
A = 1/2 × 190 × 235 × sin84°
A = 22,202.70131409 ft^2
A = 22,203 ft^2 (to the nearest whole number)
Area of the park is 22,203 ft^2
please help you will get 10 points and brainliest. and explain your answer.
Answer:
Top prism = 262 in.² Bottom prism = 478 in.²
Step-by-step explanation:
top prism:
front + back: 5 x 3 = 15
sides: 19 x 4 x 2 = 152
bottom: 19 x 5 = 95
15 + 152 + 95 = 262
bottom prism:
front + back: 5 x 6 x 2 = 60
sides: 19 x 6 x 2 = 228
top + bottom: 19 x 5 x 2 = 190
60 + 228 + 190 = 478
We wish to see if the dial indicating the oven temperature for a certain model of oven is properly calibrated. Four ovens of this model are selected at random. The dial on each is set to 300 °F, and, after one hour, the actual temperature of each is measured. The temperatures measured are 305 °F, 310 °F, 300 °F, and 305 °F. Assuming that the actual temperatures for this model when the dial is set for 300° are Normally distributed with mean μ, we test whether the dial is properly calibrated at 5% of significance level.
Actual Temp: 305, 310, 300, 305
Required:
a. Based on the data, calculate the sample standard deviation and standard error of X bar (round them into two decimal places) Standard Deviation: Standard Error:
b. What is a 95% confidence interval for μ? (upper and lower bound)
c. Provide your test statistic and P-value
d. State your conclusion clearly (statistical conclusion and its interpretation).
e. Even if 5% of significance level looks like default of test, we can use different significance levels as well. If we change the significance level into 10% (= 0.1), how does it affect your conclusion?
Answer:
a. Standard deviation: 4.082
Standard error: 2.041
b. The 95% confidence interval for the actual temperature is (298.5, 311.5).
Upper bound: 311.5
Lower bound: 298.5
c. Test statistic t=2.45
P-value = 0.092
d. There is no enough evidence to claim that the dial of the oven is not properly calibrated. The actual temperature does not significantly differ from 300 °F.
e. If we use a significance level of 10% (a less rigorous test, in which the null hypothesis is rejected with with less requirements), the conclusion changes and now there is enough evidence to claim that the dial is not properly calibrated.
This happens because now the P-value (0.092) is smaller than the significance level (0.10), given statististical evidence for the claim.
Step-by-step explanation:
The mean and standard deviation of the sample are:
[tex]M=\dfrac{1}{4}\sum_{i=1}^{4}(305+310+300+305)\\\\\\ M=\dfrac{1220}{4}=305[/tex]
[tex]s=\sqrt{\dfrac{1}{(n-1)}\sum_{i=1}^{4}(x_i-M)^2}\\\\\\s=\sqrt{\dfrac{1}{3}\cdot [(305-(305))^2+(310-(305))^2+(300-(305))^2+(305-(305))^2]}\\\\\\ s=\sqrt{\dfrac{1}{3}\cdot [(0)+(25)+(25)+(0)]}\\\\\\ s=\sqrt{\dfrac{50}{3}}=\sqrt{16.667}\\\\\\s=4.082[/tex]
We have to calculate a 95% confidence interval for the mean.
The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.
The sample mean is M=305.
The sample size is N=4.
When σ is not known, s divided by the square root of N is used as an estimate of σM (standard error):
[tex]s_M=\dfrac{s}{\sqrt{N}}=\dfrac{4.082}{\sqrt{4}}=\dfrac{4.082}{2}=2.041[/tex]
The degrees of freedom for this sample size are:
[tex]df=n-1=4-1=3[/tex]
The t-value for a 95% confidence interval and 3 degrees of freedom is t=3.18.
The margin of error (MOE) can be calculated as:
[tex]MOE=t\cdot s_M=3.18 \cdot 2.041=6.5[/tex]
Then, the lower and upper bounds of the confidence interval are:
[tex]LL=M-t \cdot s_M = 305-6.5=298.5\\\\UL=M+t \cdot s_M = 305+6.5=311.5[/tex]
The 95% confidence interval for the actual temperature is (298.5, 311.5).
This is a hypothesis test for the population mean.
The claim is that the actual temperature of the oven when the dial is at 300 °F does not significantly differ from 300 °F.
Then, the null and alternative hypothesis are:
[tex]H_0: \mu=300\\\\H_a:\mu\neq 300[/tex]
The significance level is 0.05.
The sample has a size n=4.
The sample mean is M=305.
As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=4.028.
The estimated standard error of the mean is computed using the formula:
[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{4.082}{\sqrt{4}}=2.041[/tex]
Then, we can calculate the t-statistic as:
[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{305-300}{2.041}=\dfrac{5}{2.041}=2.45[/tex]
The degrees of freedom for this sample size are:
[tex]df=n-1=4-1=3[/tex]
This test is a two-tailed test, with 3 degrees of freedom and t=2.45, so the P-value for this test is calculated as (using a t-table):
[tex]\text{P-value}=2\cdot P(t>2.45)=0.092[/tex]
As the P-value (0.092) is bigger than the significance level (0.05), the effect is not significant.
The null hypothesis failed to be rejected.
There is not enough evidence to support the claim that the actual temperature of the oven when the dial is at 300 °F does not significantly differ from 300 °F.
If the significance level is 10%, the P-value (0.092) is smaller than the significance level (0.1) and the effect is significant.
The null hypothesis is rejected.
There is enough evidence to support the claim that the actual temperature of the oven when the dial is at 300 °C does not significantly differ from 300 °C.