A teacher figures that final grades in the chemistry department are distributed as: A, 25%; B, 25%;C, 40%;D, 5%; F, 5%. At the end of a randomly selected semester, the following number of grades were recorded. Calculate the chi-square test statistic x^2 to determine if the grade distribution for the department is different than expected. Use α = 0.01.


Grade A B C D F
Number 36 42 60 14 8

a. 6.87
b. 0.6375
c. 5.25
d. 4.82

Answers

Answer 1

Answer:

[tex]E_{A} =0.25*160=40[/tex]  

[tex]E_{B} =0.25*160=40[/tex]

[tex]E_{C} =0.4*160=64[/tex]

[tex]E_{D} =0.05*160=8[/tex]  

[tex]E_{F} =0.05*160=8[/tex]  

And now we can calculate the statistic:  

[tex]\chi^2 = \frac{(36-40)^2}{40}+\frac{(42-40)^2}{40}+\frac{(60-64)^2}{64}+\frac{(14-8)^2}{8}+\frac{(8-8)^2}{8} =5.25[/tex]  

The answer would be:

c. 5.25

Step-by-step explanation:

The observed values are given by:

A: 36

B: 42

C: 60

D: 14

E: 8

Total =160

We need to conduct a chi square test in order to check the following hypothesis:  

H0: There is no difference in the proportions for the final grades

H1: There is a difference in the proportions for the final grades

The level of significance assumed for this case is [tex]\alpha=0.01[/tex]  

The statistic to check the hypothesis is given by:  

[tex]\chi^2 =\sum_{i=1}^n \frac{(O_i -E_i)^2}{E_i}[/tex]  

Now we just need to calculate the expected values with the following formula [tex]E_i = \% * total[/tex]  

And the calculations are given by:  

[tex]E_{A} =0.25*160=40[/tex]  

[tex]E_{B} =0.25*160=40[/tex]

[tex]E_{C} =0.4*160=64[/tex]

[tex]E_{D} =0.05*160=8[/tex]  

[tex]E_{F} =0.05*160=8[/tex]  

And now we can calculate the statistic:  

[tex]\chi^2 = \frac{(36-40)^2}{40}+\frac{(42-40)^2}{40}+\frac{(60-64)^2}{64}+\frac{(14-8)^2}{8}+\frac{(8-8)^2}{8} =5.25[/tex]  

The answer would be:

c. 5.25

Now we can calculate the degrees of freedom for the statistic given by:  

[tex]df=(categories-1)=(5-1)=4[/tex]

And we can calculate the p value given by:  

[tex]p_v = P(\chi^2_{4} >5.25)=0.263[/tex]  

The p value is higher than the significance so we have enough evidence to FAIL to reject the null hypothesis


Related Questions

Please help will mark brainliest.

Answers

Answer:

  parallel lines both have slope 1/3; non-parallel lines both have length 5

Step-by-step explanation:

It generally works well to follow instructions.

A graph of the points shows you that the parallel sides are RA and PT. The difference between the end points of these segments are ...

  A - R = (6, 8) -(-3, 5) = (9, 3) = (Δx, Δy)

So, the slope of RA is Δy/Δx = 3/9 = 1/3

And the other difference and slope are ...

  P -T = (9, 4) -(-3, 0) = (12, 4)   ⇒   Δy/Δx = 4/12 = 1/3

The slope of RA is the same as the slope of PT, so those segments are parallel.

__

The length of segment TR can be found from the differences of the end point coordinates:

  R - T = (-3, 5) -(-3, 0) = (0, 5)

Since these points are on the same vertical line, this tells us the segment length is 5.

The other difference of coordinates is ...

  A - P = (6, 8) -(9, 4) = (-3, 4)

The distance formula tells us the length of AP is then ...

  AP = √((-3)² +4²) = √25 = 5

Non-parallel sides TR and AP have the same lengths, so the trapezoid is isosceles.

Solve for x
A) 36
B) 54
C) 72
D) 84
Ayo help a girl out

Answers

Answer:

72°

Step-by-step explanation:

This is called an isosceles triangle. This means that the 2 angles related to the equal sides, are also equal. Hence, the answer is 72°

Answer:

A

Step-by-step explanation:

Since it is isosceles triangle (two equal sides) therefore, there are 2 equal angles too which at the base (72°)

The total angle of triange is 180°

So 180-72-72=36°

At the beginning of the season,jamie pays full price for a ticket to see the panthers,her favorite baseball team.

Answers

Corrected Question

At the beginning of the season, Jamie pays full price($49.64) for a ticket to see the panthers, her favorite baseball team. Ticket prices decrease $0.41 for every game the panthers lose this season. the panthers currently have 33 wins and 31 losses.

(a)Represent the total change in the cost of a ticket given their losses.

(b) What is the cost of a ticket for the next game they play?

Answer:

(a)$(49.64-0.41x)

(b)$36.93

Step-by-step explanation:

(a)Cost of a Full Ticket =$49.64

Let x be the number of losses

The ticket price reduces by $0.41 for every loss

Therefore:

Ticket Price after x losses =$(49.64-0.41x)

Therefore, total change in the cost of a ticket given their losses=$(49.64-0.41x)

(b)For this season the Panthers has suffered 31 losses.

Number of Losses, x=31

Therefore, cost of a ticket for the next game they play

= $(49.64-0.41*31)

=49.64-12.71

=$36.93

List the four possible results of the combinations of decisions and true states of nature for a test of hypothesis. Which of the following lists the four possible results of the combinations of decisions and true states of nature for a test of​ hypothesis? A. Reject Upper H 0H0 when Upper H 0H0 is​ true; insufficient evidence to reject Upper H 0H0 when Upper H 0H0 is​ true; reject Upper H 0H0 when Upper H Subscript aHa is​ true; insufficient evidence to reject Upper H 0H0 when Upper H Subscript aHa is true B. Reject Upper H 0H0 when Upper H 0H0 is​ true; insufficient evidence to reject Upper H 0H0 when Upper H Subscript aHa is​ true; reject Upper H Subscript aHa when Upper H Subscript aHa is​ true; insufficient evidence to reject Upper H 0H0 when Upper H 0H0 is true C. Reject Upper H 0H0 when Upper H Subscript aHa is​ true; insufficient evidence to reject Upper H 0H0 when Upper H 0H0 is​ true; reject Upper H Subscript aHa when Upper H 0H0 is​ true; insufficient evidence to reject Upper H 0H0 when Upper H Subscript aHa is true D. Reject Upper H 0H0 when Upper H 0H0 is​ true; insufficient evidence to reject Upper H 0H0 when Upper H 0H0 is​ true; reject Upper H 0H0 when Upper H Subscript aHa is​ true; accept Upper H Subscript aHa when Upper H 0H0 is true

Answers

Answer:

A

Step-by-step explanation:

The combinations of decisions and true states of nature for a test of​ hypothesis is given below:

When [tex]H_o[/tex] is True, Accept [tex]H_o[/tex]When [tex]H_o[/tex] is True, Reject [tex]H_o[/tex] (Type I Error)When [tex]H_o[/tex] is False, Accept [tex]H_o[/tex] (Type II Error)When [tex]H_o[/tex] is False, Reject [tex]H_o[/tex]

Note that when [tex]H_o[/tex] is False, then the Alternate Hypothesis, [tex]H_a[/tex] is True.

Therefore Option A gives the possible combinations.

The possible choices in Option A are ordered below to correspond to the results above.

Insufficient evidence to reject [tex]H_o[/tex]  when [tex]H_o[/tex]  is​ true; Reject [tex]H_o[/tex]  when [tex]H_o[/tex]  is​ true; Type 1 Error Insufficient evidence to reject [tex]H_o[/tex]  when [tex]H_a[/tex]  is true -Type II Error Reject [tex]H_o[/tex]  when [tex]H_a[/tex]  is​ true;

Any help would be great

Answers

Answer:

30%

Step-by-step explanation:

fat ÷ total

15 ÷ 50

.3

30%

Answer:

30%

Step-by-step explanation:

To find the percent from fat, take the calories from fat and divide by the total

15/50

.3

Multiply by 100%

30%

Alguien me puede ayudar con esto por favor!!!!

Answers

Answer:

8 + 15i

Step-by-step explanation:

(-2 + 3i) + 2(5 + 6i) =

= -2 + 3i + 10 + 12i

= 8 + 15i

please help you will get 10 points and brainliest. and explain your answer.

Answers

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

(please answer as soon as possible)If two lines intersect at a point, then vertically opposite angles are always: a)Complememtary b)Supplementary c)Unequal d)Equal

Answers

Answer:

D

Step-by-step explanation:

This is the veritcal angles theorem

If a function f(x) is defined as 3x2 + x + 2, what is the value of Lim h-0 f(x+h)-f(x)/h? A. 3x + 1 B. 3x + 2 C. 6x + 1 D. 6x + 2

Answers

Answer:

[tex] f(x+h) = 3(x+h)^2 +(x+h) +2= 3(x^2 +2xh+h^2) +x+h+2[/tex]

[tex]f(x+h) = 3x^2 +6xh +3h^2 +x+h+2= 3x^2 +6xh +x+h+ 3h^2 +2[/tex]

And replacing we got:

[tex] lim_{h \to 0} \frac{3x^2 +6xh +x+h+ 3h^2 +2 -3x^2 -x-2}{h}[/tex]

And if we simplfy we got:

[tex] lim_{h \to 0} \frac{6xh +h+ 3h^2 }{h} =lim_{h \to 0} 6x + 1 +3h [/tex]

And replacing we got:

[tex]lim_{h \to 0} 6x + 1 +3h = 6x+1[/tex]

And the bet option would be:

C. 6x + 1

Step-by-step explanation:

We have the following function given:

[tex] f(x) = 3x^2 +x+2[/tex]

And we want to find this limit:

[tex] lim_{h \to 0} \frac{f(x+h) -f(x)}{h}[/tex]

We can begin finding:

[tex] f(x+h) = 3(x+h)^2 +(x+h) +2= 3(x^2 +2xh+h^2) +x+h+2[/tex]

[tex]f(x+h) = 3x^2 +6xh +3h^2 +x+h+2= 3x^2 +6xh +x+h+ 3h^2 +2[/tex]

And replacing we got:

[tex] lim_{h \to 0} \frac{3x^2 +6xh +x+h+ 3h^2 +2 -3x^2 -x-2}{h}[/tex]

And if we simplfy we got:

[tex] lim_{h \to 0} \frac{6xh +h+ 3h^2 }{h} =lim_{h \to 0} 6x + 1 +3h [/tex]

And replacing we got:

[tex]lim_{h \to 0} 6x + 1 +3h = 6x+1[/tex]

And the bet option would be:

C. 6x + 1

Answer:

6x+1

Step-by-step explanation:

Plato :)

if the distance between sydney and goulburn is 200km, find the average speed to complete the journey in 2 hours and 30 minutes

Answers

Answer:

80 km/h

Step-by-step explanation:

2 h 30 min = 2.5 h

Average speed = distance/time= 200 km/2.5 h = 80 km/h

At the beginning of year 1, Paolo invests $500 at an annual compound
interest rate of 4%. He makes no deposits to or withdrawals from the
account.
Which explicit formula can be used to find the account's balance at the
beginning of year 5? What is the balance?

Answers

Answer:

  see below

Step-by-step explanation:

The way the problem is worded, we expect "n" to represent the year number we're at the beginning of. That is the initial balance is that when n=1, and the balance at the beginning of year 5 (after interest accrues for 4 years) is the value of obtained when n=5.

After compounding interest for 4 years, the balance will be ...

  500·1.04^4 = 584.93

The matching answer choice is shown below.

Answer:

b

Step-by-step explanation:

Determine the percentage of all samples of three men that have mean brain weights within 0.1 kg of the population mean brain weight of 1.20 kg. Interpret your answer in terms of sampling error.

Answers

Answer:

Percentage of all samples of three men that have mean brain weights within 0.1 kg of the population mean brain weight of 1.20 kg = 78.5%

The sampling error is 0.08083, in terms of the sampling error, 78.5% of samples of three men will have mean brain weights within (1.24×sampling error) of the mean.

Step-by-step explanation:

Complete Question

According to one study, brain weights of men are normally distributed with mean = 1.20 kg and a standard deviation = 0.14 kg.

Determine the percentage of all samples of three men that have mean brain weights within 0.1 kg of the population mean brain weight of 1.20 kg. Interpret your answer in terms of sampling error.

Solution

The Central limit theorem allows us to say

The mean of sampling distribution is approximately equal to the population mean.

μₓ = μ = 1.20 kg

And the standard deviation of the sampling distribution is given as

σₓ = (σ/√N)

σ = population standard deviation = 0.14 kg

N = sample size = 3

σₓ = (0.14/√3) = 0.08083

Percentage of all samples of three men that have mean brain weights within 0.1 kg of the population mean brain weight of 1.20 kg, that is, percentage of all samples of three men with mean brain weights within 1.10 kg and 1.30 kg.

P(1.10 ≤ x ≤ 1.30)

We first normalize or standardize 1.10 and 1.30

The standardized score for any value is the value minus the mean then divided by the standard deviation.

For 1.10 kg

z = (x - μₓ)/σₓ = (1.10 - 1.20)/0.08083 = -1.24

For 1.30 kg

z = (x - μₓ)/σₓ = (1.30 - 1.20)/0.08083 = 1.24

To determine the required probability

P(1.10 ≤ x ≤ 1.30) = P(-1.24 ≤ z ≤ 1.24)

We'll use data from the normal distribution table for these probabilities

P(1.10 ≤ x ≤ 1.30) = P(-1.24 ≤ z ≤ 1.24)

= P(z ≤ 1.24) - P(z ≤ -1.24)

= 0.89251 - 0.10749

= 0.78502 = 78.502%

The sampling error is 0.08083, in terms of the sampling error, 78.5% of samples of three men will have mean brain weights within (1.24×sampling error) of the mean.

Hope this Helps!!!

I WILL GIVE BRAINLIEST ANSWER ASAP

Answers

Answer: B

Step-by-step explanation:

For this problem, to solve for x, you want to move all like terms to one side.

[tex]\frac{1}{4}x-\frac{1}{2}x=\frac{7}{8} +\frac{1}{8}[/tex]

Now that you have moved like terms to one side, you can directly add and subtract to combine like terms.

[tex]-\frac{1}{4} x=1[/tex]

x=-4

Answer:

[tex]x = - 4[/tex]

Second answer is correct

Step-by-step explanation:

[tex] \frac{1}{4} x - \frac{1}{8} = \frac{7}{8} + \frac{1}{2} x \\ \frac{1}{4} x - \frac{1}{2} x = \frac{1}{8} + \frac{7}{8} \\ \frac{1x - 2x}{4} = \frac{8}{8} \\ - \frac{1}{4} x = 1 \\ - 1x = 1 \times 4 \\ - 1x = 4 \\ x = - 4[/tex]

hope this helps you

A cell phone company is offering 2 different monthly plans. Each plan charges a monthly fee plus an additional cost per minute. Plan A: $ 40 fee plus $0.45 per minute Plan B: $70 fee plus $0.35 per minute a) Write an equation to represent the cost of Plan A b) Write an equation to represent the cost of Plan B c) Which plan would be least expensive for a total of 100 minutes?

*Please Show Work*

Answers

Answer:

Plan A would be the least expensive

Step-by-step explanation:

Plan A= $0.45x100= 45, 45+40=$85

Plan B= $0.35x100= 35, 35+70= %105

(Each plan is for 100 minutes)

A teacher wrote the equation 3y + 12 = 6x on the board. For what value of b would the additional equation 2y = 4x + b form a system of linear equations with infinitely many solutions?
b = –8
b = –4
b = 2
b = 6

Answers

Answer:

-8

Step-by-step explanation:

For a system to have infinitely many solutions the two equations must be the same line. We can simplify the first and second equations by dividing them by 3 and 2 respectively to get:

y + 4 = 2x

y = 2x + b/2 → y -b/2 = 2x

Since the constants must be equal, 4 = -b/2 which means b = -8.

Answer:

b=-8

Step-by-step explanation:

Given the following diagram, are and opposite rays? yes no

Answers

Answer:

Where is the diagram?

Step-by-step explanation:

Answer:

OC and OE are apposite rays so the Answer is yes

What is the equation of the line that passes through (4, 2) ) and is parallel to 3x - 2y = - 6 ?

Answers

Answer:

[tex]y=\frac{3}{2} x-4[/tex]

Step-by-step explanation:

The graph I provided shows it passes thru (4,2) and that it is parallel

Answer:

y = 3/2x -4

Step-by-step explanation:

3x - 2y = - 6

First find the slope by putting it in slope intercept form

Subtract 3x from each side

-2y = -3x-6

Divide by -2

y = -3x/-2  -6/-2

y = 3/2x +3

The slope is 3/2

Parallel lines have the same slope

We have the slope 3/2 and a point (4,2)

y = mx+b where m is the slope and b is the y intercept

y =3/2x+b

Substitute the point into the equation

2 = 3/2(4) +b

2 = 6 +b

Subtract 6

2-6 = 6-6+b

-4 =b

y = 3/2x -4

A farmer was interest in determining how many grasshoppers were in his field. He knows that the distribution of grasshoppers may not be normally distributed in his field due to growing conditions. As he drives his tractor down each row he counts how many grasshoppers he sees flying away. After several rows he figures the mean number of flights to be 57 with a standard deviation of 12. What is the probability of the farmer will count 52 or fewer flights on average in the next 40 rows down which he drives his tractor

Answers

Answer:

= 0.0041

Step-by-step explanation:

Given that:

A farmer was interest in determining how many grasshoppers were in his field. He knows that the distribution of grasshoppers may not be normally distributed in his field due to growing conditions. As he drives his tractor down each row he counts how many grasshoppers he sees flying away

mean number of flights to be 57

a standard deviation of 12

fewer flights on average in the next 40 rows

[tex]\mu = 57\\\\\sigma=12\\\\n=40[/tex]

so,

[tex]P(x<52)[/tex]

[tex]=P(\frac{x-\mu}{\sigma/\sqrt{n} } <\frac{52-57}{12/\sqrt{40} } )\\\\=P(z<\frac{-5\times6.325}{12} )\\\\=P(z<\frac{-31.625}{12})\\\\=P(z<-2.64)[/tex]

using z table

= 0.0041

The probability of the farmer will count 52 or fewer flights on average in the next 40 rows down which he drives his tractor is 0.0041 and this can be determined by using the properties of probability.

Given :

The distribution of grasshoppers may not be normally distributed in his field due to growing conditions.The mean number of flights to be 57 with a standard deviation of 12.

The probability of the farmer will count 52 or fewer flights on average in the next 40 rows down which he drives his tractor, can be determined by using the following calculations:

[tex]\rm P(x<52)=P\left (\dfrac{x-\mu}{\dfrac{\sigma}{\sqrt{n} }}<\dfrac{52-57}{\dfrac{12}{\sqrt{40} }}\right)[/tex]

[tex]\rm P(x<52)=P\left (z<\dfrac{-5\times 6.325}{12 }}\right)[/tex]

[tex]\rm P(x<52)=P\left (z<\dfrac{-31.625}{12 }}\right)[/tex]

[tex]\rm P(x<52)=P\left (z<-2.64\right)[/tex]

Now, using z-table:

P(x < 52) = 0.0041

For more information, refer to the link given below:

https://brainly.com/question/21586810

When converting measurements in the metric system, you can move the decimal point to the left or to the right. Why? Select all that apply. A. When converting from smaller to larger units, you are dividing by a power of 10. B. Moving a decimal point is the same as adding or subtracting. C. The metric system is based on powers of 10. D. When converting from larger to smaller units, you are multiplying by a power of 10.

Answers

Answer:

This has multiple answers, A, C, And D

Step-by-step explanation:

Answer:

It is definitely A, C, and D.

Step-by-step explanation:

I just answered this question and got it right. I hope this helps and please mark brainliest!

Use the quadratic formula to find both solutions to the quadratic equation given below. 2x^2+3x-5=0

Answers

Answer:

[tex] x =\frac{-b \pm \sqrt{b^2 -4ac}}{2a}[/tex]

Where a = 2 , b= 3, c= -5, replacing we have this:

[tex]x =\frac{-3 \pm \sqrt{(-3)^2 -4(2)(-5)}}{2*2}[/tex]

And simplifying we got:

[tex] x = \frac{-3 \pm \sqrt{49}}{4}[/tex]

And the two solutions are:

[tex] x_1 = \frac{-3+7}{4}= 1[/tex]

[tex] x_2 = \frac{-3-7}{4}= -\frac{5}{2}[/tex]

And the correct options are:

B and C

Step-by-step explanation:

We have the following equation given:

[tex] 2x^2 +3x -5=0[/tex]

And if we use the quadratic formula given by:

[tex] x =\frac{-b \pm \sqrt{b^2 -4ac}}{2a}[/tex]

Where a = 2 , b= 3, c= -5, replacing we have this:

[tex]x =\frac{-3 \pm \sqrt{(-3)^2 -4(2)(-5)}}{2*2}[/tex]

And simplifying we got:

[tex] x = \frac{-3 \pm \sqrt{49}}{4}[/tex]

And the two solutions are:

[tex] x_1 = \frac{-3+7}{4}= 1[/tex]

[tex] x_2 = \frac{-3-7}{4}= -\frac{5}{2}[/tex]

And the correct options are:

B and C

Answer:

B and C

Step-by-step explanation:

5 inches is blank times big as 1 inch

Answers

Answer:

5 inches is 5 times as big as 1 inch

The graph of Ax), shown below, resembles the graph of G(X) = x, but it has
been stretched and shifted. Which of the following could be the equation of
Fx)?

Answers

Answer:

sorry'but I don't know the answer

Determine the​ value(s) of h such that the matrix is the augmented matrix of a consistent linear system. [Start 2 By 3 Matrix 1st Row 1st Column 1 2nd Column 4 3rd Column negative 2 2nd Row 1st Column 3 2nd Column h 3rd Column negative 6 EndMatrix ]

Answers

Answer:

Step-by-step explanation:

Consider the augments matrix (the right most column is  the extra vector).

[tex]\left[\begin{matrix} 1 & 4 & -2 \\3 & h & -6\end{matrix}\right][/tex]

By multypling the first row by 3 and substracting it from the second row and saving the result in the second row we get the matrix

[tex]\left[\begin{matrix} 1 & 4 & -2 \\0 & h-12 & 0\end{matrix}\right][/tex]

Note that since the value of the third column in the second row is 0, any value of h gives us a consistent system. An inconsistent system is when we get a row of zeros that is equal to a number different from 0.

If 5=3+2,then 3+2=5. What is the truth value

Answers

Answer:

true

Step-by-step explanation:

Graph the line with slope -1/3 and y -intercept 6 .

Answers

Answer:

plot a point at 6 up from (0,0) and then go down one and over three places then plot another point- and so on - and so on

Step-by-step explanation:

To graph the line using the slope and intercept, first understand what the slope and intercept mean:

Slope is how steep or flat the line appears on the graph.

A very high or low slope (100 or -100) will be very steep on the graph.A slope very close to zero (0.0001 or -0.0001) will be very flat on the graph.A positive slope will travel northeast and southwest (for linear equations).A negative slope will travel northwest and southeast (for linear equations).

The y-intercept is the point at which the line hits the y-axis. In this equation, the line hits the y-axis at positive 6, which means that the point is (0, 6).

You can use a method called "rise over run" to graph. The slope is negative one over three, so the line will "rise" negative one units after "running" three units.

So, for every one unit down, the line will travel three units to the right.

Graph this from the point (0, 6), your y-intercept, and plot the points according to the slope:

which quadrilateral will always have four reflection symmetry

Answers

Step-by-step explanation:

a rectangle has reflectional symmetry when reflected over the line through the midpoints of its opposite sides

Answer: A square always has a four reflection symmetry no matter the size.

Customer arrivals at a bank are random and independent; the probability of an arrival in any one-minute period is the same as the probability of an arrival in any other one-minute period. Answer the following questions, assuming a mean arrival rate of three customers per minute.

Required:
a. What is the probability of exactly three arrivals in one-minute period?
b. What is the probability of at least three arrivals in a one-minute period?

Answers

Answer:

a)0.2240

b)0.5768

Step-by-step explanation:

Given:

µ=3

Poison probability is given by :

[tex]f_k=\frac{\mu^ke^-^\mu}{k!}[/tex]

a) Evaluating at k=3

[tex]f(3)=\frac{3^3e^-^3}{3!} \approx 0.2240[/tex]

b)Evaluating at k=0,1,2:

[tex]f(0)=\frac{3^0e^-^3}{0!} \approx 0.0498[/tex]

[tex]f(1)=\frac{3^1e^-^3}{1!} \approx 0.1494[/tex]

[tex]f(2)=\frac{3^2e^-^3}{2!} \approx 0.2240[/tex]

Use complement rule:

P(x≥3)= 1 - f(0) - f(1) - f(2)= 1- 0.0498 - 0.1494 - 0.2240 =0.5768

Scientists think that robots will play a crucial role in factories in the next several decades. Suppose that in an experiment to determine whether the use of robots to weave computer cables is feasible, a robot was used to assemble 507 cables. The cables were examined and there were 9 defectives. If human assemblers have a defect rate of 0.035 (3.5%), does this data support the hypothesis that the proportion of defectives is lower for robots than humans

Answers

Answer:

The data support the hypothesis that the proportion of defectives is lower for robots than humans.

Step-by-step explanation:

To know if the proportion of defectives is lower for robots than humans so as to prove if the hypothesis is true.

From the data given:

Total number of cables a robot assembled = 507

Defectives = 9

To get the defect rate =  the number of defects divided by the total number of cables, multiplied by 100.

Defect rate =  (9 / 507) x 100 = 0.01775 x 100

Defect rate for the robot = 1.775‬%

From the question, a robot was used and the defect rate after the calculation is 1.775‬%. While for humans, the defect rate is 3.5%. This implies, if humans were used to assembling the same 507 cables, there will be 17.745‬ defectives.

x / 507 = 3.5%

x (defectives) = 17.745‬

Therefore, the data support the hypothesis that the proportion of defectives is lower for robots than humans.

A rocket is launched from a tower. The height of the rocket, y in feet, is related to the time after launch, x in seconds, by the given equation. Using this equation, find the maximum height reached by the rocket , to the nearest 100th of a foot. y=-16x^2+230x+112

Answers

Answer:

The maximum height reached by the rocket is of 938.56 feet.

Step-by-step explanation:

The height y, after x seconds, is given by a equation in the following format:

[tex]y(x) = ax^{2} + bx + c[/tex]

If a is negative, the maximum height is:

[tex]y(x_{v})[/tex]

In which

[tex]x_{v} = -\frac{b}{2a}[/tex]

In this question:

[tex]y(x) = -16x^{2} + 230x + 112[/tex]

So

[tex]a = -16, b = 230, c = 112[/tex]

Then

[tex]x_{v} = -\frac{230}{2*(-16)} = 7.1875[/tex]

[tex]y(7.1835) = -16*(7.1835)^{2} + 230*7.1835 + 112 = 938.56[/tex]

The maximum height reached by the rocket is of 938.56 feet.

help me please!!!! Dan's car depreciates at a rate of 8% per year. By what percentage has Dan's car depreciated after 3 years? Give your answer to the nearest percent.

Answers

Answer:

22%

Step-by-step explanation:

Car's price is reduced by 8% or 0.92 times a year

after 3 years it will make:

0.92³= 0.778688≈ 0.78 times

or

0.78 = 1- 0.22price decrease = 22%

Answer:

Hello!

Here is your answer:

22%

I hope I was able to help you.  If not, please let me know!

Step-by-step explanation:

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