The belief is that the mean number of hours per week of part-time work of high school seniors in a city is 10.5 hours. Data from a simple random sample of 23 high school seniors indicated that their mean number of part-time work was 11.5 with a standard deviation of 1.4. Test whether these data cast doubt on the current belief. (use α = 0.05)
Required:
a. State your null and alternative hypotheses.
b. Sketch the rejection region.
c. Calculate the test statistic. Plot this value in your sketch in part b.
d. Determine the P-value for your test.
e. State your conclusions clearly in complete sentences.
Answers
Answer:
a) See step by step explanation
b) See annex
c) t(s) = 3,4255
d) p- value = 0,00146 or 0,15 %
e) See step by step explanation
Step-by-step explanation:
As n < 30 we use a t-student distribution
Population mean μ₀ = 10,5
Sample size n = 23
Degree of freedom n - 1 = 22
Sample mean μ = 11,5
Sample standard deviation s = 1,4
Confidence Interval 95 %
a) Null Hypothesis H₀ μ = μ₀
Alternative Hypothesis Hₐ μ > μ₀
As CI = 95 % α = 5% or α = 0,05
We are solving a one tail-test
With df = 22 and α = 0,05 in t-table we find t(c) = 1,7171
c) t(s) = ( μ - μ₀ ) / s / √n
t(s) = ( 11,5 - 10,5 ) / 1,4 / √23
t(s) = 1 * 4,7958 / 1,4
t(s) = 3,4255
We compare t(s) and t(c)
t(s) > t(c) and t(s) is in the rejection region
Then we reject the null hypothesis.
d) P-value for t(s) = 3,4255 is from t-table equal to:
We find for df = 22 α = 0,001 and α = 0,005
values of t
t 3,505 2, 819 Δt = 0,686
α 0,001 0,005 Δα = 0,004
with these values we interpolate by rule of three
0,686 ⇒ 0,004
(3,505 - 3,4255) ⇒ x
x = 0,000463
and P-value = 0,00146 or 0,15 %
e) The p-value indicates we are far away to consider the accptance of H₀
Related Questions
The probability of rolling two dice at the same time and getting a 4 with either die or the sum of the dice is 6
Answers
Answer:
Suppose that the first die we roll comes up as a 1. The other die roll could be a 1, 2, 3, 4, 5, or 6. Now suppose that the first die is a 2. The other die roll again could be a 1, 2, 3, 4, 5, or 6. We have already found 12 potential outcomes, and have yet to exhaust all of the possibilities of the first die. But with a second dice, there will be 24 different possibilities.
Step-by-step explanation:
1 2 3 4 5 6
1 (1, 1) (1, 2) (1, 3) (1, 4) (1, 5) (1, 6)
2 (2, 1) (2, 2) (2, 3) (2, 4) (2, 5) (2, 6)
3 (3, 1) (3, 2) (3, 3) (3, 4) (3, 5) (3, 6)
4 (4, 1) (4, 2) (4, 3) (4, 4) (4, 5) (4, 6)
5 (5, 1) (5, 2) (5, 3) (5, 4) (5, 5) (5, 6)
6 (6, 1) (6, 2) (6, 3) (6, 4) (6, 5) (6, 6)
the distance around the edge of a circular pond is 88m. the radius in meters is ?
(a)88π
(b)176π
(c)88/π
(d)88/2π
Answers
Answer: (d) 88/ 2π
Step-by-step explanation:
Perimeter = 88m
Perimeter of a circle = 2πr
88 = 2π x r
r = 88 / 2π
Answer:
88/2π = r
Step-by-step explanation:
The circumference is 88 m
The circumference is given by
C = 2*pi*r
88 = 2 * pi *r
Divide each side by 2 pi
88 / 2pi = 2 * pi *r / 2 * pi
88 / 2 pi = r
The Rocky Mountain district sales manager of Rath Publishing Inc., a college textbook publishing company, claims that the sales representatives make an average of 41 sales calls per week on professors. Several reps say that this estimate is too low. To investigate, a random sample of 38 sales representatives reveals that the mean number of calls made last week was 42. The standard deviation of the sample is 3.9 calls. Using the 0.025 significance level, can we conclude that the mean number of calls per salesperson per week is more than 41?H0 : µ = 40
H1 : µ > 401. Compute the value of the test statistic. 2. What is your decision regarding H0?
Answers
Answer:
1. Test statistic t=1.581.
2. The null hypothesis H0 failed to be rejected.
There is not enough evidence to support the claim that the mean number of calls per salesperson per week is significantly more than 41.
NOTE: if the null hypothesis is µ = 40, there is enough evidence to support the claim that the mean number of calls per salesperson per week is significantly more than 40 (test statistic t=3.161).
Step-by-step explanation:
This is a hypothesis test for the population mean.
The claim is that the mean number of calls per salesperson per week is significantly more than 41.
Then, the null and alternative hypothesis are:
[tex]H_0: \mu=41\\\\H_a:\mu> 41[/tex]
The significance level is 0.025.
The sample has a size n=38.
The sample mean is M=42.
As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=3.9.
The estimated standard error of the mean is computed using the formula:
[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{3.9}{\sqrt{38}}=0.633[/tex]
Then, we can calculate the t-statistic as:
[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{42-41}{0.633}=\dfrac{1}{0.633}=1.581[/tex]
The degrees of freedom for this sample size are:
[tex]df=n-1=38-1=37[/tex]
This test is a right-tailed test, with 37 degrees of freedom and t=1.581, so the P-value for this test is calculated as (using a t-table):
[tex]\text{P-value}=P(t>1.581)=0.061[/tex]
As the P-value (0.061) is bigger than the significance level (0.025), the effect is not significant.
The null hypothesis failed to be rejected.
There is not enough evidence to support the claim that the mean number of calls per salesperson per week is significantly more than 41.
For µ = 40:
This is a hypothesis test for the population mean.
The claim is that the mean number of calls per salesperson per week is significantly more than 40.
Then, the null and alternative hypothesis are:
[tex]H_0: \mu=40\\\\H_a:\mu> 40[/tex]
The significance level is 0.025.
The sample has a size n=38.
The sample mean is M=42.
As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=3.9.
The estimated standard error of the mean is computed using the formula:
[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{3.9}{\sqrt{38}}=0.633[/tex]
Then, we can calculate the t-statistic as:
[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{42-40}{0.633}=\dfrac{2}{0.633}=3.161[/tex]
The degrees of freedom for this sample size are:
[tex]df=n-1=38-1=37[/tex]
This test is a right-tailed test, with 37 degrees of freedom and t=3.161, so the P-value for this test is calculated as (using a t-table):
[tex]\text{P-value}=P(t>3.161)=0.002[/tex]
As the P-value (0.002) is smaller than the significance level (0.025), the effect is significant.
The null hypothesis is rejected.
There is enough evidence to support the claim that the mean number of calls per salesperson per week is significantly more than 40.
ABCD is a kite.
B
O
y = [?]
A 40°
C
Х
Enter the number
that belongs in
the green box.
D
Answers
Answer:
50°
Step-by-step explanation:
ABCD is a kite.
Therefore, AB = BC
[tex]\therefore m\angle BCA= m\angle BAC = 40\degree \\
\because BD \perp AC.. (Diagonals \: of\: kite) \\
\therefore y + 90\degree + m\angle BCA = 180\degree \\
\therefore y + 90\degree + 40\degree = 180\degree \\
\therefore y = 180\degree - 130\degree \\
\huge\red {\boxed {y = 50\degree}} [/tex]
4b • 0.5a 2ab 2a2b 2ab2 2a2b2
Answers
Answer:
(4b)•(0.5a) = (4•0.5)(a)(b) = 2ab
Step-by-step explanation:
A girl walks 800 m on a bearing of 129°.
Calculate how far: a east b south she is from
her starting point.
Answers
Answer: a) 503.2m
b) 621.6m
Step-by-step explanation:
The diagram representing the scenario is shown in the attached photo.
A represents her starting point.
CD = x = how far east she is from her starting point
BC = y = how far south she is from her starting point
Angle BAC = 180 - 129 = 51°
Angle ACD = angle BAC = 51° because they are alternate angles
To determine x, we would apply the cosine trigonometric ratio
Cos 51 = x /800
x = 800Cos51 = 800 × 0.629 = 503.2m
To determine y, we would apply the sine trigonometric ratio
Sin 51 = y /800
y = 800Sin51 = 800 × 0.777 = 621.6m
The weights of college football players are normally distributed with a mean of 200 pounds and a standard deviation of 50 pounds. If a college football player is randomly selected, find the probability that he weighs between 170 and 220 pounds. Round to four decimal places.
Answers
Answer:
0.3811 = 38.11% probability that he weighs between 170 and 220 pounds.
Step-by-step explanation:
When the distribution is normal, we use the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this question, we have that:
[tex]\mu = 200, \sigma = 50[/tex]
Find the probability that he weighs between 170 and 220 pounds.
This is the pvalue of Z when X = 220 subtracted by the pvalue of Z when X = 170.
X = 220
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{220 - 200}{50}[/tex]
[tex]Z = 0.4[/tex]
[tex]Z = 0.4[/tex] has a pvalue of 0.6554
X = 170
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{170 - 200}{50}[/tex]
[tex]Z = -0.6[/tex]
[tex]Z = -0.6[/tex] has a pvalue of 0.2743
0.6554 - 0.2743 = 0.3811
0.3811 = 38.11% probability that he weighs between 170 and 220 pounds.
a. dashed line, shade below
b. dashed line, shaded above
c. solid line, shade above
d. solid line, shade below
Answers
Answer:
the answer is A
Step-by-step explanation:
List price is 45$ if the sales tax rate is 7% how much is the sales tax in dollars
Answers
Answer:
3.15 dollars
Step-by-step explanation:
The sales tax rate is 7% = 0.07
So, we need to multiply the listed price and the sales tax rate.
= 45 * 0.07 = 3.150 (3.15)
Hope this helps and please mark as the brainliest
I want to fence in a rectangular vegetable patch. The fencing for the east and west sides costs $2 per foot, and the fencing for the north and south sides costs only $1 per foot. I have a budget of $40 for the project. What is the largest area I can enclose
Answers
Answer:
largets area is 32 feet cubed
Step-by-step explanation:
8=4 foot 2 for each side w and e and 32feet n and s 16 each side
A U.S. dime has a diameter of about 18 millimeters. What is the area of one side of a dime to the nearest square millimeter? Use 3.14 as an approximation for pi. The area of one side of a U.S. dime is approximately _____ square millimeters.
Answers
Area of one side of a U.S. dime is approximately 254 square millimeters.
What is Circle?A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre.
Given that U.S. dime has a diameter of about 18 millimeters.
We need to find the area of one side of a dime to the nearest square millimeter.
Diameter=18 millimeters
Diameter is two times of radius
D=2R
18=2R
Divide both sides by 2
Radius is 9 millimeters.
Area of dime=πr²
=3.14×(9)²
=3.14×81
=254 square millimeters.
Hence, area of one side of a U.S. dime is approximately 254 square millimeters.
To learn more on Circles click:
https://brainly.com/question/11833983
#SPJ5
What is a square root
Answers
Find the surface area of the solid shown or described. If necessary, round to the nearest tenth. A.348m^2 B.484m^2 C.180.7m^2 D.262m^2
Answers
Answer: 484m²
Step-by-step explanation: This is a question on solid shape.
The surface area of a cone is the same thing as the perimeter of the cone ie, the materials required to construct the cone.
Formula for the surface area of the cone = πrl + πr², ( the circular base )
From.the diagram,
r = 7.1m , l = 14.6m, π = 3.142
Now substitute for those values in.the formula above
SA = πrl + πr²
= 3.142 × 7.1 × 14.6 + 3.142 × 7.1²
= 325.6997 + 158.388
= 484.09
Now to the nearest tenth meter,
SA = 484m²
Two spheres of the same outer diameter, one solid and the other hollow, are completely immersed in the water. We can affirm:
a) The hollow receives less push
b) The hollow receives more push
c) Both receive the same push
d) The solid receives less push
Answers
Answer:
c) Both receive the same push
Step-by-step explanation:
The buoyancy force is equal to the weight of the displaced fluid:
B = ρVg
where ρ is the density of the water, V is the volume of displaced water, and g is the acceleration due to gravity.
Since both spheres displace the same amount of water, they have equal buoyancy forces.
Find the coordinates of the point on a circle with radius 4 at an angle of 2pi/3
{Please help!!}
Answers
Answer:
The coordinates of the point on a circle with radius 4 at an angle of [tex]\frac{2\pi}{3}[/tex] radians are x = -2 and y = 3.464.
Step-by-step explanation:
This problem ask us to determine the rectangular coordinates from polar coordinates. The polar coordinates of the point in rectangular form is expressed by the following expression:
[tex](x,y) = (r\cdot \cos \theta, r\cdot \sin \theta)[/tex]
Where [tex]r[/tex] and [tex]\theta[/tex] are the radius of the circle and the angle of inclination of the point with respect to horizontal, measured in radians. If [tex]r = 4[/tex] and [tex]\theta = \frac{2\pi}{3}\,rad[/tex], the coordinates of the point are:
[tex](x,y) = \left(4\cdot \cos \frac{2\pi}{3},4\cdot \sin \frac{2\pi}{3} \right)[/tex]
[tex](x,y) = (-2, 3.464)[/tex]
The coordinates of the point on a circle with radius 4 at an angle of [tex]\frac{2\pi}{3}[/tex] radians are x = -2 and y = 3.464.
Which expression is the simplest form of -(x + 5) - 3(x + 2)?
Answers
Answer:
-4x -11
Step-by-step explanation:
-(x + 5) - 3(x + 2)
Distribute
-x -5 -3x -6
Combine like terms
-x-3x -5-6
-4x -11
Answer:
[tex] = - (4x + 11)[/tex]
Step-by-step explanation:
[tex]-(x + 5) - 3(x + 2) \\ -x - 5 - 3x - 6 \\ -x - 3x -5 - 6 \\ - 4x - 11 \\ = -(4x + 11)[/tex]
Simplify.
In e =
In e 2x=
In 1 =
Answers
Answer:
ln e = 1
ln e 2x = 2x
ln 1 = 0
Step-by-step explanation:
ln e
ln(2.718282) = 1
In e 2x
ln(2.718282)(2)x = 2x
ln 1 = 0
if a^2+b^2+c^2=169. find a, given that b=2√2, 3√c=9.
Answers
Answer:
a = ±4√5
Step-by-step explanation:
Solve for c.
3√c = 9
√c = 9/3
√c = 3
c = 3²
c = 9
Put b=2√2 and c=9, solve for a.
a² + (2√2)² + 9² = 169
a² + 8 + 81 = 169
a² = 169 - 81 - 8
a² = 80
a = ±√80
a = ±4√5
a. What is a residual? b. In what sense is the regression line the straight line that "best" fits the points in a scatterplot? a. What is a residual?
Answers
Answer:
a. A residual is how far off a point is from the expected value. For example, if I were to estimate the weight of my Southeastern Lubber Grasshopper, I would say it's maybe 5 ounces. But, in reality, it might be 4 ounces. So, the residual would be the reality minus the prediction, or 4 - 5, or -1 ounce.
b. The regression line is the line of predicted values for the points in the scatterplot. It tries to predict the points and make all the points be on the line.
Hope this helps!
Given the equation y = 7 sec(6x– 30)
The period is:
The horizontal shift is:
Answers
Answer:
The period is of [tex]\frac{\pi}{3}[/tex] units.
The horizontal shift is of 30 units to the left.
Step-by-step explanation:
The secant function has the following general format:
[tex]y = A\sec{(Bx + C)}[/tex]
A represents the vertical shift.
C represents the horizontal shift. If C is positive, the shift is to the right. If it is negative, it is to the left.
The period is [tex]P = \frac{2\pi}{B}[/tex]
In this question:
[tex]y = 7\sec{6x - 30}[/tex]
So [tex]B = 6, C = -30[/tex]
Then [tex]P = \frac{2\pi}{6} = \frac{\pi}{3}[/tex]
The period is of [tex]\frac{\pi}{3}[/tex] units.
The horizontal shift is of 30 units to the left.
C equals 2 pi r; Cequals62.8 (Circumference of a circle)
Answers
Answer:
about 10
Step-by-step explanation:
62.8 = 2 pi r/2
62.8/2 = pi r
31.4/pi = pi r/pi
about 10 = r
A card is drawn randomly from a standard 52-card deck. Find the probability of the given event.
(a) The card drawn is a king.
(b) The card drawn is a face card.
(c) The card drawn is not a face card.
Answers
Answer:
(a) [tex]\frac{1}{13}[/tex]
(b) [tex]\frac{3}{13}[/tex]
(c) [tex]\frac{10}{13}[/tex]
Step-by-step explanation:
The probability of an event B occurring is given by;
P(B) = [tex]\frac{n(E)}{n(S)}[/tex]
Where;
P(B) = probability of the event B
n(E) = number of favourable outcomes
n(S) = total number of events in the sampled space.
From the question, the card is drawn randomly from a standard 52-card deck. The probability of
(a) drawing a "king" card is analyzed as follows.
Let the event of drawing the "king" card be B.
In a standard 52-card deck, the number of cards that are of type king is 4. i.e 1 from the diamond pack, 1 from the spade pack, 1 from the heart pack and 1 from the club pack.
Therefore, the number of favourable outcomes is 4, while the total number of events in the sampled space is 52.
The probability of drawing a "king" card, P(B) is;
P(B) = [tex]\frac{4}{52}[/tex]
P(B) = [tex]\frac{1}{13}[/tex]
(b) drawing a "face" card is analyzed as follows.
Let the event of drawing the "face" card be B.
In a standard 52-card deck, a face card can either be a Jack, Queen or a King. There are 4 Jack cards, 4 Queen cards and 4 King cards in the deck. The number of cards that are of type face is 12.
Therefore, the number of favourable outcomes is 12, while the total number of events in the sampled space is 52.
The probability of drawing a "face" card, P(B) is;
P(B) = [tex]\frac{12}{52}[/tex]
P(B) = [tex]\frac{3}{13}[/tex]
(c) drawing a card that is not a "face" is analyzed as follows;
The sum of the probability of drawing a face card and the probability of not drawing a face card is always 1.
Let the event of drawing a "face" card be B and the event of not drawing a "face" card be C.
P(B) + P(C) = 1
P(C) = 1 - P(B)
From (b) above, the P(B) = [tex]\frac{3}{13}[/tex]
Therefore,
P(C) = 1 - [tex]\frac{3}{13}[/tex]
P(C) = [tex]\frac{10}{13}[/tex]
researchers are interested in the average size of a certain species of mouse. They collect the length and gender of each mouse. What is the parameter likely estimated and the sample statistic
Answers
Answer:
E. The parameter is μmale - μfemale and the statistic is xmale - xfemale.
Step-by-step explanation:
The sample statistic is a piece of information about the individuals or objects that were selected from a given population. The sample is just a fraction of the total population. Since it is a herculean task studying an entire population, the sample forms a manageable size that allows us to have an insight into the entire population. The sample statistics are now the piece of information about the sample being studied such as the average, mean, median, or mode. The sample statistics have to be as specific as possible of the factors being measured. In the question, we would have to obtain the mean of both the male and female genders. This gives us an insight into the population under study.
The parameter, on the other hand, is a description of the entire population being studied. For example, we might want to determine the population mean. That is the factor we seek to measure. It is represented by the sign mu (μ).
My question is probably obvious but I don't know it. What is the z axis
Answers
Answer:
z-Axis. The axis in three-dimensional Cartesian coordinates which is usually oriented vertically. Cylindrical coordinates are defined such that the -axis is the axis about which the azimuth coordinate. is measured.
Step-by-step explanation:
The straight line L has equation y = 1/2x+7 The straight line M is parallel to L and passes through the point (0, 3). Write down an equation for the line M.
Answers
Answer:
y = [tex]\frac{1}{2}[/tex] x + 3
Step-by-step explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
y = [tex]\frac{1}{2}[/tex] x + 7 ← is in slope- intercept form
with slope m = [tex]\frac{1}{2}[/tex]
Parallel lines have equal slopes
line M crosses the y- axis at (0, 3) ⇒ c = 3
y = [tex]\frac{1}{2}[/tex] x + 3 ← equation of line M
PLEASE QUICK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Which number completes the system of linear inequalities represented by the graph? y > 2x – 2 and x + 4y > -12 -3 4 6
Answers
Answer:
-12
Step-by-step explanation:
Edge 2021
A sample of 26 offshore oil workers took part in a simulated escape exercise, and their escape time (unit: second) were observed. The sample mean and sample standard deviation are 370.69 and 24.36, respectively. Suppose the investigators had believed a priori that true average escape time would be at most 6 minutes. Does the data contradict this prior belief? Assuming normality, test the appropriate hypotheses using the rejection region method at a significance level of 0.05.
Answers
Answer:
Yes, it contradict this prior belief as there is enough evidence to support the claim that the true average escape time is significantly higher than 6 minutes.
Test statistic t=2.238>tc=1.708.
The null hypothesis is rejected.
Step-by-step explanation:
This is a hypothesis test for the population mean.
The claim is that the true average escape time is significantly higher than 6 minutes (360 seconds).
Then, the null and alternative hypothesis are:
[tex]H_0: \mu=360\\\\H_a:\mu> 360[/tex]
The significance level is 0.05.
The sample has a size n=26.
The sample mean is M=370.69.
As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=24.36.
The estimated standard error of the mean is computed using the formula:
[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{24.36}{\sqrt{26}}=4.777[/tex]
Then, we can calculate the t-statistic as:
[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{370.69-360}{4.777}=\dfrac{10.69}{4.777}=2.238[/tex]
The degrees of freedom for this sample size are:
[tex]df=n-1=26-1=25[/tex]
The critical value for a right-tailed test with a significance level of 0.05 and 25 degrees of freedom is tc=1.708. If the test statistic is bigger than 1.708, it falls in the rejection region and the null hypothesis is rejected.
As the test statistic t=2.238 is bigger than the critical value t=1.708, the effect is significant. The null hypothesis is rejected.
There is enough evidence to support the claim that the true average escape time is significantly higher than 6 minutes (360 seconds).
What is the slope of this line?
Answers
Answer:
3/2
Step-by-step explanation:
We can find the slope of this line by using two points
(1,-3) and (3,0)
m = (y2-y1)/(x2-x1)
= (0- -3)/(3 -1)
= (0+3)/(3-1)
= 3/2
what it 17.15 in 12hour clock
Answers
Answer:
Step-by-step explanation:
Hello friend
The answer is 5:15 in 12 hour clock
Answer:
5:15 PM
Step-by-step explanation:
12:00 + 5:00
17:00 in 12 hour clock is 5:00 PM.
15 minutes + 5:00 PM
⇒ 5:15 PM
the intersection of the two legs of the right triangle and the red segment is the _________ of the triangle shown
Answers
Answer:
b median
Step-by-step explanation:
Answer:
orthocenter
Step-by-step explanation:
The red segment is an altitude of the triangle, as are the two legs. The intersection point of the altitudes is the orthocenter.
__
This is basically a vocabulary question.
altitude - the perpendicular segment from a vertex to the opposite side (or its extension)median - the segment joining a vertex with the midpoint of the opposite sidecentroid - the point where medians meetorthocenter - the point where altitudes meet