The city manager of Shinbone has received a complaint from the local union of firefighters to the effect that they are underpaid. Not having much time, the city manager gathers the records of a random sample of 27 firefighters and finds that their average salary is $38,073 with a standard deviation of $575. If she knows that the average salary nationally is $38,202, how can she respond to the complaint
Answer:
She can answer, after performing the hypothesis test, that there is not enough evidence to support the claim that the city firefighters salary is significantly lower than the national average.
Step-by-step explanation:
She can statistically test the claim of the firefighters to see if it has statistical evidence.
This is a hypothesis test for the population mean.
The claim is that the city firefighters salary is significantly lower than the national average.
Then, the null and alternative hypothesis are:
[tex]H_0: \mu=38202\\\\H_a:\mu< 38202[/tex]
The significance level is 0.1. Is less conservative than 0.05, for example, so if there is little evidence, the null hypothesis with be rejected.
The sample has a size n=27.
The sample mean is M=38073.
As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=575.
The estimated standard error of the mean is computed using the formula:
[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{575}{\sqrt{27}}=110.659[/tex]
Then, we can calculate the t-statistic as:
[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{38073-38202}{110.659}=\dfrac{-129}{110.659}=-1.17[/tex]
The degrees of freedom for this sample size are:
df=n-1=27-1=26
This test is a left-tailed test, with 26 degrees of freedom and t=-1.17, so the P-value for this test is calculated as (using a t-table):
[tex]\text{P-value}=P(t<-1.17)=0.127[/tex]
As the P-value (0.127) is bigger than the significance level (0.1), the effect is not significant.
The null hypothesis failed to be rejected.
There is not enough evidence to support the claim that the city firefighters salary is significantly lower than the national average.
HELP!!! PLEASE!!!
The U.S. Federal Income Tax is a progressive tax, which means that higher incomes are taxed at higher percent rates.
The table shows the 2018 Federal Income Tax rates that are applied to the incomes of unmarried individuals.
Tuan is an unmarried man who earned a taxable income of $48$48,000000 during 2018.
Use the table to complete the statements below.
Answer:
10%$29,175$2,046$6,499.50Step-by-step explanation:
a) The %tax comes from the "Rate" column on the line "up to $9525". It is 10%.
__
b) Simply compute the difference shown:
$38,700 -$9,525 = $29,175
__
c) 22% of $9,300 is ...
0.22 × $9,300 = $2,046
__
d) The total from the three previous calculations is ...
$952.50 +3,501.00 +2,046.00 = $6,499.50
Answer:
10%
$29,175
$2,046
$6,499.50
got it right on ttm.
Step-by-step explanation:
just believe me it works
Please answer this correctly
Answer:
4
Step-by-step explanation:
Set the height of the missing bar to 4 as there are 4 quantities between 21-25.
01
The list below shows the prices of T-shirts at a clothing store.
{8, 10, 10, 12, 15, 15, 18)
Which statement best describes the mean of this ser?
the difference between the least and greatest prices
the sum of the prices
the quotient of the difference between the least and greatest prices divided by 7
the sum of the prices divided by 7
dem
Answer:
the sum of the prices divided by 7
Step-by-step explanation:
The mean is the sum of the elements of a set, divided by the number of elements in the set. This set has 7 members, so its mean is ...
the sum of the prices divided by 7
find x.
8
2radius3
8
8radius3
(hurry plz, will give brainliest) -15pts-
Answer:
Answere is X= 8
Step-by-step explanation:
Use sine law
Sin(angle) = Opposite/ Hypotenuse
Sin (30) = 4 /X
X = 4 / sin (30)
X = 8
Question: A box contains 160 Iphone XR's.
60% of the IPhones are Forest Green.
How many IPhones are Forest Green?
Answer:
96
Step-by-step explanation:
60% * 160 = 0.6 * 160 = 96.
Answer:
None
Step-by-step explanation:
There is no Forest Green iPhone XR's only the 11 Pros have that color.
The sum of two numbers is odd. Can the quotient of the two numbers be an odd number?
Answer: No.
Step-by-step explanation:
I guess that here we have the statement:
If the sum of two numbers is odd----> can their quotient be an odd number?
first, for n an integer number, we have that:
an odd number can be written as 2n + 1
an even number can be written as 2n.
The sum of two numbers is only odd if one of them is odd and the other even.
Then we have a number that is 2n and other that is 2k + 1, for n and k integer numbers.
Now, let's see if the quotient can also be an odd number.
One way to think this is:
There is an odd number such that when we multiply it by another odd number, the result is an even number?
no, and i can prove it as:
let 2k + 1 be an odd number, and 2j + 1 other.
the product is:
(2k + 1)*(2j + 1) = 2*(2*k*j + k + j) + 1
and as k and j are integers, also does 2*k*j + k + j, so:
2*(2*k*j + k + j) + 1 is an odd number.
This says that the product of two odd numbers is always odd, then we never can have that the quotient between an even number and an odd number is odd.
convert 3.9cm to hm
Answer:
Step-by-step explanation:
0.00039 hm
Answer:
0.00039 hm is ur answer....
3.9 cm to 0.00039 hm...
Mark me as Brainlist...
Question 1 of 20 :
Select the best answer for the question.
1. Divide7/15 by 3/5
OA%
O B./25
O c. 75/21
O D.21/75
Answer:
7/9
Step-by-step explanation:
7/15 ÷ 3/5
Copy dot flip
7/15 * 5/3
7/3 * 5/15
7/3 * 1/3
7/9
simplify (6^7)^3
will give brainlist
Answer:
The answer is D.
Step-by-step explanation:
You have to apply Indices Law,
[tex] { ({a}^{m}) }^{n} \: ⇒ \: {a}^{mn} [/tex]
So for this question :
[tex] { ({6}^{7}) }^{3} [/tex]
[tex] = {6}^{7 \times 3} [/tex]
[tex] = {6}^{21} [/tex]
Louis had 19 dogs. He feeds them with 38 pounds of biscuits. If there are 4 more
dogs, then how much more pounds of biscuit are needed?
Answer:
14
Step-by-step explanation:
Answer:
Which of these factors will affect the friction on a road
Step-by-step explanation:
the length of a ruler is 170cm,if the ruler broke into four equal parts.what will be the sum of the length of three parts
Answer:
Step-by-step explanation:Srry it's bit rough...
How do you write or break down this decimal:
45.50 =
Step-by-step explanation:
45.50
Converting decimal
45.50 x 100 = 4550
Andrei wants to fill a glass tank with marbles, and then fill the remaining space with water. WWW represents the volume of water Andrei uses (in liters) if he uses nnn marbles. W=32-0.05nW=32−0.05nW, equals, 32, minus, 0, point, 05, n What is the glass tank's volume?
Before Andrei adds the marbles to the glass tank, the glass tank was empty. This means that the volume of the empty tank is when n = 0 and the volume is 32 liters.
Given that:
[tex]W = 32 - 0.05n[/tex]
A linear function is represented as:
[tex]y = b + mx[/tex]
Where
[tex]b \to[/tex] y intercept
Literally, the y intercept is the initial value of the function.
In this function, the y intercept means the initial volume of the glass tank before filling it with marbles.
Compare [tex]y = b + mx[/tex] and [tex]W = 32 - 0.05n[/tex]
[tex]b = 32[/tex]
This means that the volume of the glass tank is 32 liters.
Read more about linear functions at:
https://brainly.com/question/21107621
Answer:
0.05
Step-by-step explanation:
Please answer this correctly
Answer:
Set the height up to 4
Step-by-step explanation:
Since there are 4 numbers between 1-5, set the height up to 4
Answer:
4 temperature recordings.
Step-by-step explanation:
2, 2, 4, 5
There are 4 recordings in the range of 1-5°C.
Please help. I’ll mark you as brainliest if correct!
Answer:
a = 13
b = 0
Step-by-step explanation:
Conjugate of -3 + 2i is -3 - 2i
(-3 + 2i) (-3 - 2i)
We need to expand:
9 + 6i + -6i + -4i^2
-4i^2 =(-4)(-1) = 4
9 + 4 = 13
a = 13
b = 0
A comparison is made between two bus lines to determine if arrival times of their regular buses from Denver to Durango are off schedule by the same amount of time. For 51 randomly selected runs, bus line A was observed to be off schedule an average time of 53 minutes, with standard deviation 17 minutes. For 60 randomly selected runs, bus line B was observed to be off schedule an average of 60 minutes, with standard deviation 13 minutes. Do the data indicate a significant difference in average off-schedule times? Use a 5% level of significance.
a. Level of significance, null and alternative hypothesis
b. What sampling distribution will you use? What assumptions are you making? What is the value of the sample test statistic?
c. Find or estimate the P-value
d. Based on your answers to part a and c will you reject or fail to reject the null hypothesis? Are the data statistically significant at level alpha?
e. Interpret your conclusion in the context of the application
Answer:
a) Level of significance α=0.05
Two-tailed test, with null and alternative hypothesis:
[tex]H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2\neq 0[/tex]
b) Student's t distribution. We assume equal variances for both populations, independent sampled values and populations normally distributed.
Test statistic t=-2.4
c) P-value = 0.018
d) Rejection of the null hypothesis.
The data is statistically significant.
e) There is evidence to conclude there is significant difference in average off-schedule times between the bus lines. The difference we see in the samples seems not due to pure chance.
Step-by-step explanation:
This is a hypothesis test for the difference between populations means.
The claim is that there is a significant difference in average off-schedule times for this bus lines.
Then, the null and alternative hypothesis are:
[tex]H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2\neq 0[/tex]
The significance level is 0.05.
The sample 1 (bus line A), of size n1=51 has a mean of 53 and a standard deviation of 17.
The sample 2 (bus line B), of size n2=60 has a mean of 60 and a standard deviation of 13.
The difference between sample means is Md=-7.
[tex]M_d=M_1-M_2=53-60=-7[/tex]
The estimated standard error of the difference between means is computed using the formula:
[tex]s_{M_d}=\sqrt{\dfrac{\sigma_1^2}{n_1}+\dfrac{\sigma_2^2}{n_2}}=\sqrt{\dfrac{17^2}{51}+\dfrac{13^2}{60}}\\\\\\s_{M_d}=\sqrt{5.667+2.817}=\sqrt{8.483}=2.913[/tex]
Then, we can calculate the t-statistic as:
[tex]t=\dfrac{M_d-(\mu_1-\mu_2)}{s_{M_d}}=\dfrac{-7-0}{2.913}=\dfrac{-7}{2.913}=-2.4[/tex]
The degrees of freedom for this test are:
[tex]df=n_1+n_2-1=51+60-2=109[/tex]
This test is a two-tailed test, with 109 degrees of freedom and t=-2.4, so the P-value for this test is calculated as (using a t-table):
[tex]\text{P-value}=2\cdot P(t<-2.4)=0.018[/tex]
As the P-value (0.018) is smaller than the significance level (0.05), the effect is significant.
The null hypothesis is rejected.
There is enough evidence to support the claim that there is a significant difference in average off-schedule times for this bus lines.
What is the greatest number of right angles a triangle can contain?
A. 0
B. 1
C. 3
D. 2
The answer is B..........
Answer:
B. 1
Step-by-step explanation:
If it was more than one it wouldn't be a triangle.
Outcome
0
1
5
10
1000
Probability
0.33
0.32
0.24
0.10
0.01
Which is the expected value of the random variable with the given probability distribution?
a.
5.65
c.
12.52
b.
100.44
d.
5
Answer:
The expected value of the random variable with the given probability distribution = 12 .52
Step-by-step explanation:
Given data
x : 0 1 5 10 1000
p(x) : 0.33 0.32 0.24 0.10 0.01
The expected value of the given random variable of given probability distribution
E(X) = ∑ x p ( X = x)
E(X) = 0 × 0.33 + 1 × 0.32 + 5 × 0.24 + 10× 0.10 + 1000×0.01
E (X) = 12.52
The lifespan of a car battery averages six years. Suppose the batterylifespan follows an exponential distribution.(a) Find the probability that a randomly selected car battery will lastmore than four years.(b) Find the variance and the 95th percentile of the battery lifespan.(c) Suppose a three-year-old battery is still going strong. (i) Find theprobability the battery will last an additional five years. (ii) Howmuch longer is this battery expected to last
Answer:
Step-by-step explanation:
Let X denote the life span of a car battery and it follows and exponential distribution with average of 6 years.
Thus , the parameter of the exponential distribution is calculated as,
μ = 6
[tex]\frac{1}{\lambda} =6[/tex]
[tex]\lambda = \frac{1}{6}[/tex]
a) The required probability is
[tex]P(X>4)=1-P(X\leq 4)\\\\=1-F(4)\\\\1-(1-e^{- \lambda x})\\\\=e^{-\frac{4}{6}[/tex]
= 0.513
Hence, the probability that a randomly selected car battery will last more than four years is 0.513
b) The variance of the battery span is calculated as
[tex]\sigma ^2=\frac{1}{(\frac{1}{\lambda})^2 }\\\\\sigma ^2=\frac{1}{(\frac{1}{6})^2 } \\\\=6^2=36[/tex]
The 95% percentile [tex]x_{a=0.05}[/tex] (α = 5%) of the battery span is calculated
[tex]x_{0.05}=-\frac{log(\alpha) }{\lambda} \\\\=-\frac{log(0.05)}{1/6} \\\\=-6log(0.05)\\\\=17.97 \ years[/tex]
c)
Let [tex]X_r[/tex] denote the remaining life time of a car battery
i)the probability the battery will last an additional five years is calculated below
[tex]P(X_r>5)=e^{-5\lambda}\\\\=e^{-\frac{5}{6} }\\\\=0.4346[/tex]
ii) The average time that the battery is expected to last is calculated
[tex]E(X_r)=\frac{1}{\lambda} \\\\=6[/tex]
average of a data set was 40, and that standard deviation was 10, what else could you derive from that information.
Answer:
[tex] \bar x = 40, s =10[/tex]
And from these values we can estimate the sample variance like this:
[tex] s^2 = 10^2 =100[/tex]
And we can also estimate the coeffcient of variation given by:
[tex] \hat{CV} =\frac{s}{\bar x}[/tex]
And replacing we got:
[tex] \hat{CV} = \frac{10}{40}= 0.25[/tex]
And this coefficient is useful in order to see the variability in terms of the mean for this case since is lower than 1 we can conclude that this variation around the mean is low.
Step-by-step explanation:
For this case we have the following info given:
[tex] \bar x = 40, s =10[/tex]
And from these values we can estimate the sample variance like this:
[tex] s^2 = 10^2 =100[/tex]
And we can also estimate the coeffcient of variation given by:
[tex] \hat{CV} =\frac{s}{\bar x}[/tex]
And replacing we got:
[tex] \hat{CV} = \frac{10}{40}= 0.25[/tex]
And this coefficient is useful in order to see the variability in terms of the mean for this case since is lower than 1 we can conclude that this variation around the mean is low.
What’s the correct answer for this question?
Answer:
C.
Step-by-step explanation:
1/2r = 2π/Cb
What is an equivalent function to f(x)=(x-2)^3
Answer:
x^3-6x^2-4x-8
Step-by-step explanation:
First you would multiply (x-2) by itself (x-2) to get
x^2-2x-2x+4
then you would combine like terms
x^2-4x+4
Then you would multiply that by x-2
(x^2-4x+4)(x-2)
x^3-2x^2-4x^2-8x+4x-8
then you combine like terms
x^3-6x^2-4x-8
What is the perimeter of the shape below?
Answer:
I think it is 288.6 ft. Lol hope this helps
Step-by-step explanation:
Find the value of z Subscript alpha divided by 2 that corresponds to a confidence level of 89.48%.
Answer:
For this case we know that the confidence level is 89.48% or 0.8948 and the significance would be: [tex] \alpha=1-0.8948 = 0.1052[/tex] and the value of [tex]\alpha/2 =0.0526[/tex]
Now we need to find a quantile in the normal standard distribution who accumulate 0.0526 of the area on each tail of the normal standard distribution and we got:
[tex] z_{\alpha/2}= \pm 1.62015[/tex]
And we can use the following excel code for example:
"=NORM.INV(0.0526,0,1)"
Step-by-step explanation:
For this case we know that the confidence level is 89.48% or 0.8948 and the significance would be: [tex] \alpha=1-0.8948 = 0.1052[/tex] and the value of [tex]\alpha/2 =0.0526[/tex]
Now we need to find a quantile in the normal standard distribution who accumulate 0.0526 of the area on each tail of the normal standard distribution and we got:
[tex] z_{\alpha/2}= \pm 1.62015[/tex]
And we can use the following excel code for example:
"=NORM.INV(0.0526,0,1)"
It appears that people who are mildly obese are less active than leaner people. One study looked at the average number of minutes per day that people spend standing or walking. Among mildly obese people, minutes of activity varied according to the N(373, 61) distribution. Minutes of activity for lean people had the N(525, 104) distribution. Within what limits do the active minutes for 95% of the people in each group fall
Answer:
Among mildly obese people, 95% of the people have between 251 and 495 minutes of activity per day.
Among lean people, 95% of the people have between 317 and 733 minutes of activity per day.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
Within what limits do the active minutes for 95% of the people in each group fall
By the Empirical Rule, within 2 standard deviations of the mean.
Mildly obese:
Mean = 373, standard deviation = 61.
373 - 2*61 = 251 minutes
373 + 2*61 = 495 minutes
Among mildly obese people, 95% of the people have between 251 and 495 minutes of activity per day.
Lean people:
Mean = 525, standard deviation = 104
525 - 2*104 = 317 minutes
525 + 2*104 = 733 minutes
Among lean people, 95% of the people have between 317 and 733 minutes of activity per day.
please very soon I offer the crown !!! + 10 points urgently !!!
Answer:
d. 10th e. 26th
Step-by-step explanation:
22-12=10
12+14=26
5.44 Teaching descriptive statistics: A study compared five different methods for teaching descriptive statistics. The five methods were traditional lecture and discussion, programmed textbook instruction, programmed text with lectures, computer instruction, and computer instruction with lectures. 45 students were randomly assigned, 9 to each method. After completing the course, students took a 1-hour exam. (a) What are the hypotheses for evaluating if the average test scores are different for the different teaching methods?
Answer:
The null hypothesis is that all the different teaching methods have the same average test scores.
H0: μ1 = μ2 = μ3 = μ4 = μ5
The alternative hypothesis is that at least one of the teaching methods have a different mean.
Ha: at least one mean is different. (μ1 ≠ μi)
Step-by-step explanation:
The null hypothesis (H0) tries to show that no significant variation exists between variables or that a single variable is no different than its mean. While an alternative Hypothesis (Ha) attempt to prove that a new theory is true rather than the old one. That a variable is significantly different from the mean.
For the case above, let μ represent the average test scores for the teaching methods:
The null hypothesis is that all the different teaching methods have the same average test scores.
H0: μ1 = μ2 = μ3 = μ4 = μ5
The alternative hypothesis is that at least one of the teaching methods have a different mean.
Ha: at least one mean is different. (μ1 ≠ μi)
What’s the degree of the rotation?
Answer: The answer is C 90
Step-by-step explanation: Rotations is ¼ and the Radians is π/2
Devon wants to build a ramp with the dimensions shown. How much wood does he need?
The image of the ramp with dimensions is missing, so i have attached it.
Answer:
680 in² of wood is needed.
Step-by-step explanation:
The way to find how much wood would be needed by devon would be to find the total surface area of the ramp.
From the attached image,
Let's find the area of the 2 triangles first;
A1 = 2(½bh) = bh = 15 x 8 = 120 in²
Area of the slant rectangular portion;
A2 = 17 x 14 = 238 in²
Area of the base;
A3 = 15 × 14 = 210 in²
Area of vertical rectangle;
A4 = 8 × 14 = 112 in²
Total Surface Area = A1 + A2 + A3 + A4 = 120 + 238 + 210 + 112 = 680 in²
