The quality control manager at a light bulb factory needs to estimate the mean life of a batch (population) of light bulbs. We assume that the population standard deviation is 100 hours. A random sample of 64 light bulbs from the batch yields a sample mean of 350. a) Construct a 95% confidence interval for the population mean of light bulbs in this batch. b) Do you think that the manufacturer has the right to state that the average life of the light bulbs is 400 hours

Answers

Answer 1

Answer:

a)95%  confidence intervals for the population mean of light bulbs in this batch

(325.5 ,374.5)

b)

The calculated value Z = 4 > 1.96 at 0.05 level of significance

Null hypothesis is rejected

The manufacturer has not right to take the average life of the light bulbs is 400 hours.

Step-by-step explanation:

Given sample size n = 64

Given  mean of the sample x⁻ = 350

Standard deviation of the Population σ = 100 hours

The tabulated value Z₀.₉₅ = 1.96

95%  confidence intervals for the population mean of light bulbs in this batch

[tex](x^{-} - Z_{\frac{\alpha }{2} } \frac{S.D}{\sqrt{n} } , x^{-} + Z_{\frac{\alpha }{2} }\frac{S.D}{\sqrt{n} } )[/tex]

[tex](350 - 1.96\frac{100}{\sqrt{64} } , 350 + 1.96\frac{100}{\sqrt{64} } )[/tex]

[tex](350 -24.5, 350 +24.5)[/tex]

(325.5 ,374.5)

b)

Explanation:-

Given mean of the Population μ = 400

Given sample size n = 64

Given  mean of the sample x⁻ = 350

Standard deviation of the Population σ = 100 hours

Null hypothesis : H₀:The manufacturer has right to take the average life of the light bulbs is 400 hours.

μ = 400

Alternative Hypothesis: H₁: μ ≠400

The test statistic

[tex]Z = \frac{x^{-}-mean }{\frac{S.D}{\sqrt{n} } }[/tex]

[tex]Z = \frac{350 -400}{\frac{100}{\sqrt{64} } }[/tex]

|Z| = |-4|

The tabulated value   Z₀.₉₅ = 1.96

The calculated value Z = 4 > 1.96 at 0.05 level of significance

Null hypothesis is rejected.

Conclusion:-

The manufacturer has not right to take the average life of the light bulbs is 400 hours.


Related Questions

Ms Davis is doing an activity with her statistic students where she gives them a 20 question multiple top choice test and they know none of the answers. Students need to guess on every question and each question has 5 possible choices, 1 of the which is correct.

What is the mean and standard deviation of the number of questions that each student gets correct?

Answers

Answer:

The mean and standard deviation of the number of questions that each student gets correct are 4 and 1.789 respectively.

Step-by-step explanation:

Let the random variable X be defined as the number of correct answers marked by a student.

It is provided that each question has 5 possible choices, 1 of the which is correct.

Then the probability of marking thee correct option is:

[tex]P(X)=\frac{1}{5}=0.20[/tex]

There are a total of n = 20 questions to be answered.

As the students does not the answer to any question, they would be guessing for each question. This implies that for a random question, all the five options has the equal probability of being correct and each of the five options can be correct independently from the other.

All these information above indicates that the random variable X follows a Binomial distribution with parameters n = 20 and p = 0.20.

The mean and standard deviation of a Binomial distribution are:

[tex]\mu=np\\\\\sigma=\sqrt{np(1-p)}[/tex]

Compute the mean and standard deviation of the random variable X as follows:

[tex]\mu=np=20\times 0.20=4\\\\\sigma=\sqrt{np(1-p)}=\sqrt{20\times 0.20\times(1-0.20)}=1.789[/tex]

Thus, the mean and standard deviation of the number of questions that each student gets correct are 4 and 1.789 respectively.

The mean will be "4" and the standard deviation will "1.789".

According to the question,

The probability of making 3 correct options will be:

→ [tex]P(X) = \frac{1}{5}[/tex]

            [tex]= 0.20[/tex]

Total number of questions,

n = 20

As we know,

The mean will be:

→ [tex]\mu = np[/tex]

By substituting the values, we get

     [tex]= 20\times 0.20[/tex]

     [tex]= 4[/tex]

and,

The standard deviation will be:

→ [tex]\sigma = \sqrt{np(1-p)}[/tex]

      [tex]= \sqrt{20\times 0.20\times (1-0.20)}[/tex]

      [tex]= 1.789[/tex]

Thus the responses above are correct.

Learn more about standard deviation here:

https://brainly.com/question/20896613

add 5 1/2 kg to 450g​

Answers

1kg = 1000g

51/2 kg= 51/2×1000=51×500=25500g

25500g+450g= 25950g

Answer:

[tex]5950g[/tex]

Step-by-step explanation:

[tex]5 \frac{1}{2} kg \\ = 5kg \: 500g \\ = 5500g[/tex]

Now let's add.

[tex] \: \: \: \: \: \: 5500g \\ + \: \: \: \: 450g \\ =5950 g[/tex]

So the correct answer is,

[tex] = 5950g = 5kg \: 950g[/tex]

hope this helps

brainliest appreciated

good luck! have a nice day!

Find the surface area of the pyramid to the nearest whole number.

Answers

Answer:

i think its 248m^2

Step-by-step explanation:

Please help ASAP! I will mark Brainliest! Please READ the question THEN answer CORRECTLY! No guessing!

Answers

Answer:

C.  [tex]\frac{\sqrt{5} }{8}[/tex]

Step-by-step explanation:

This expression can be rewritten as [tex]\frac{\sqrt{5} }{\sqrt{64} }[/tex].

Since the square root of 5 is prime and does not have any perfect square factors, it cannot be simplified. However, the square root of 64 is equal to 8, so our final simplified radical expression would be [tex]\frac{\sqrt{5} }{8}[/tex], which is option C.

HOPE THIS HELPED! :)

Answer:

C is the answer

Step-by-step explanation:

You have to rewrite as [tex]\sqrt{5}[/tex]/[tex]\sqrt{64}[/tex]. Then you have to simplify the denominator which is 8. That is how you get your answer.

Hope this helps.

You need to be taller than 48" to ride the roller coaster. Which of the following inequalities shows the height Susan has to be to ride the roller coaster.

h < 48"

h > 48"

h ≤ 48"

h ≥ 48"

Answers

Answer:

> 48"

Step-by-step explanation:

> represents greater than 48"

Please help ASAP! I will mark Brainliest! Please answer CORRECTLY! No guessing!

Answers

Answer:

Option D: 5591.93

Step-by-step explanation:

The best way to understand this question is to apply the formula in an indirect manner;

P - Principle number, Starting Value

T - Time

I - Interest

Let us convert the interest into decimal form, such that 3.8% is shifted two decimal points to the right ⇒ 0.038. Now add 1 to this value to get ⇒ 1.038. By PEDMAS, you would first raise this value to the span of 3 years as such:

(1.038)^3 = 1.118386872.......

The final step would by to multiply the starting value (investment $) $ 5,000 by this continuing value of 1.118386872:

5,000(1.118386872) = 5591.93436 ⇒ Rounded to (About) 5591.93

Answer:D

Step-by-step explanation:

principal=p=$5000

Rate=r=3.8%

Time=n=3 years

amount=a

a=p(1+r/100)^n

a=5000(1+3.8/100)^3

a=5000(1+0.038)^3

a=5000(1.038)^3

a=5000 x 1.038 x 1.038 x 1.038

a=5591.93

a=$5591.93

A sphere is inscribed in a cube. Explain the relationship between the surface areas of the two solid figures

Answers

Answer:

No one knows. Jk just go look at the other brainly links. the question has already been asked and answered so you can go see them there.

Step-by-step explanation:

:)

Priscilla’s grandmother’s fruit salad recipe calls for one part apple, one part orange, four parts strawberry, two parts cherry, and three parts grape. Priscilla uses the same measuring cup to measure all of the fruit, so one part is equal to one cup of diced fruit. In this exercise, you will compare the quantities in the recipe to understand ratios better.

Answers

Answer:

There are 11 parts of fruit: 4-strawberry, 3- grape, 2, cherry, 1- apple, 1-orange 4/11 from the entine quantity of fruits- strawberry

3/11-grapes

2/11- cherries

1/11- apples

1/11- oranges } ⇒ the quantity of oranges and apples are equal Hope it helps ;>

the midpoint of AB is point P at (-16,6) if point A is at (-10,8) what are the coordinates of point B?

Answers

Answer:

Denote B(x, y), we have:

-10 + x = 2 x (-16) => x = -22

  8 + y = 2 x 6 => y = 4

=> B(-22, 4)

Hope this helps!

:)

If you roll a die three times, what is the probability of rolling three ONES?

(Give your answer as a decimal, rounded to the nearest thousandth. That is, rounded to three decimal places.)

Answers

Answer:

0.004

Step-by-step explanation:

The probability of rolling any number is 1/6 so that times 3 is 1/216 that as a decimal i 0.004

Rewrite the percentage in the sentence below as a decimal.
The 20 overseas investors own 7.2% of the business.

Answers

Answer:

0.072

Step-by-step explanation:

Answer:0.072

Step-by-step explanation:

7.2% = 7.2/100

7.2 ➗ 100=0.072

please answer these, it is urgent

Answers

Answer: 1 is D

2 is c

Step-by-step explanation:

A spinner is divided into 8 equal sections numbered 1 to 8. About how many times would you expect the pointer to land on a number less than 6 if the pointer is spun 30 times.

Answers

Answer:

The answer is

6.25×30= 18.75

I'm not sure but this is what I think

Subtracting by adding up 65-39

Answers

Answer:

26

Step-by-step explanation:

In order to subtract by adding up 65-39, we need to add -39 to the value of 65. This can be rewritten in this way;

65+(-39)

The equation above is similar to the one given because the product of a minus and a plus sign will still give us back a minus sign.

on solving;

65+(-39) = 26

A bag contains 10 Yellow, 4 Green and 7 Blue marbles. Find the following probabilies.
P(blue)

Answers

Answer:

1/3

Step-by-step explanation:

The total number of marbles

10+4+7 = 21

P(blue) = blue marbles / total marbles

            = 7 / 21

            = 1/3

55 POINTS IF YOU GET RIGHT THEN GOATED AND BRAINIEST!!

Answers

Answer:

17 i would say it is D

18 i belive it is B

19 it is c

20 A

Points X( -6, -4), Y( -2, -8), Z( 2,-4) are the vertices of a right triangle. What is the area of XYZ? Round to the nearest tenth.

Answers

Answer:

16

Step-by-step explanation:

distance between point x and z is 8 units

distance between point z and y is 4 units

8 * 4 = 32

formula for area of a triangle (l * w)/2

plugin: (8 * 4)/2 = 16

If f(x)=9x+2, What is the value of the function when x=4?

If f(x)=9x+2, for what value of x is the value of the function 29?

Answers

Answer:

1) 38

2) 3

Step-by-step explanation:

f(x)=36+2

f(x)=38

29=9x+2

27=9x

x=3

Question: What is the value of the function at x=−2?

Answer: y=2

Step-by-step explanation: I took the test.

*THIS IS THE CORRECT ANSWER. PLEASE DON'T ANSWER 3. IT IS WRONG!*

Carpetland carpet installers incur an average cost of $300 for each carpet installed. Joan Chin, the firm’s vice president, proposes a new procedure for installations, which she hopes will be more efficient. Joan plans to run a trial and hopes that the results of a trial period will enable her to conclude with a level of significance of 0.05 that the new procedure reduces the average cost to install a carpet. If Joan's hypothesis test results in a Type II error, what would this mean?

Answers

Answer:

A Type II error happens when the null hypothesis failed to be rejected, although it is false and the alternative hypothesis is true.

In this context, would be that the test does not give enough evidence to support the claim that the new procedure reduces the average cost, although it really does reduces it.

The new procedure is effective, but the sample does not give enough evidence.

Step-by-step explanation:

Solve each equation.
13 = -2w

Answers

Answer:

w = -6.5

Step-by-step explanation:

We want to get rid of the coefficient of w so that we can solve for w. To do that, let's divide both sides of the equation by -2. When we do so, we get -13/2 = w. Hope this helps!

How many boys are there in an introductory geology course if 360 students are enrolled and there are five boys to every seven girls?

Answers

Answer:150 branliest

Step-by-step explanation:

Answer:

150

Step-by-step explanation:

360/(5+7)=30

30*5=150

Healthy grains is planning a new design for its best-selling oatmeal. It has four containers to choose from

Answers

The question is incomplete:

Healthy Grains is planning a new design for its best-selling oatmeal. It has four containers to choose from. It costs the company $0.03 per cubic inch of oatmeal to fill a container. The company does not want the new container to cost more than $4.00 to fill. Which container should the company use? Use 3.14 for Pi.

Container A: A cylinder with height 7 inches and diameter 5 inches.

Container B: A cylinder with height 10 inches and B = 12.57 inches squared.

Container C: A cylinder with height 5.5 inches and radius 4 inches.

Container D: A cylinder with height 6 inches and radius 3 inches.

Answer:

Container B

Step-by-step explanation:

To find the answer you have to calculate the volume of each container and then, multiply that for $0.03 that is the cost per cubic inch to fill a container.

The formula to calculate the volume of a cylinder is:

V=πr^2h, where

r= radius

h= height

πr^2= base area

Container A:

The radius is half the diameter, so 5/2=2.5.

V= 3.14*(2.5^2)*7= 137.37

Cost= 137.37*0.03= 4.12

Container B:

12.57 inches is the base area, so:

V= 12.57*10= 125.7

Cost= 125.7*0.03= 3.77

Container C:

V= 3.14*(4^2)*5.5= 276.32

Cost= 276.32*0.03= 8.28

Container D:

V= 3.14*(3^2)*6

V= 169.56*0.03= 5.08

According to this, the answer is that the container that the company should use is container B because it costs less than $4.00 to fill.

Find the greatest common factor of the
following monomials:
34c3 2c5

Answers

Answer:2c^2

Step-by-step explanation:

34c^3 and 2c^5

34c^3=2 x 16 x c x c^2

2c^5=2 x c^2 x c^3

Greatest common factor =2 x c^2

Greatest common factor =2c^2

What is the solution to the system of equations?

3 x + 10 y = negative 47. 5 x minus 7 y = 40.
(1, –5)
(1, 5)
(–1, –5)
(–1, 5)

Answers

Answer:

  (1, –5)

Step-by-step explanation:

It is relatively easy to try the offered solutions to see what works.

(1, -5)

  3(1) +10(-5) = -47 . . . true

  5(1) -7(-5) = 40 . . . true

(1, -5) is the solution

_____

As a check, you can try some of the other choices:

(1, 5)

  3(1) +10(5) ≠ -47

(-1, -5)

  3(-1) +10(-5) ≠ -47

(-1, 5)

  3(-1) +10(5) ≠ -47

None of the other choices works in the first equation, so they're not the solution.

Answer:

(1,-5)

Step-by-step explanation:

1)get desmos

2)put in numbers

3)where they intersect is the answer.

easy as pie... oh wait pie ain't easy...

easy as ramen

please help me I would really appreciate it this really affects my grade need the answer the ASAP

Answers

Answer:

27/6, 4 3/6, or simplified version 4 1/2

Step-by-step explanation:

Always convert the mixed numbers into an improper fraction before you solve, this makes it easier to solve.

2 4/6 = 16/6

1 5/6 = 11/6

3 4/6 = 22/6

Now we solve. Remember, you do NOT add the denominator, leave it as 6 not 12. You only add the numerator.

16/6 + 11/6 = 27/6, 4 3/6 or simplified as 4 1/2

22/6 + 5/6 = The same as above.

Which fraction equals a repeating decimal?
30/50
13/25
5/30
13/10

Answers

Answer:

5/30

Step-by-step explanation:

5/30 = 1/6 =0.166666666...

The fraction equals a repeating decimal is 5/30.

What are decimals?

A decimal numeral system is the standard system for denoting integer and non-integer numbers. The way of denoting numbers in the decimal system is often referred to as decimal notation.

Now the given fractions are,

30/50

13/25

5/30

13/10

Converting them into decimals we get,

30/50 = 0.6

13/25 = 0.52

5/30 = 0.1666..

13/10 = 1.3

Thus the repeating decimal is 0.1666..

So, the fraction with repeating decimal is 5/30 = 0.1666..

Thus, the fraction equals a repeating decimal is 5/30.

To learn more about fraction :

brainly.com/question/1301963

#SPJ2

A grocery store has an average sales of $8000 per day. The store introduced several advertising campaigns in order to increase sales. To determine whether or not the advertising campaigns have been effective in increasing sales, a sample of 64 days of sales was selected. It was found that the average was $8300 per day. From past information, it is known that the standard deviation of the population is $1200. The p-value is

Answers

Answer:

The p-value of the test is 0.023.

Step-by-step explanation:

In this case we need to determine whether the addition of several advertising campaigns increased the sales or not.

The hypothesis can be defined as follows:

H₀: The stores average sales is $8000 per day, i.e. μ = 8000.

Hₐ: The stores average sales is more than $8000 per day, i.e. μ > 8000.

The information provided is:

 [tex]n=64\\\bar x=\$8300\\\sigma=\$1200[/tex]

As the population standard deviation is provided, we will use a z-test for single mean.

Compute the test statistic value as follows:

 [tex]z=\frac{\bar x-\mu}{\sigma/\sqrt{n}}=\frac{8300-8000}{1200/\sqrt{64}}=2[/tex]

The test statistic value is 2.

Decision rule:

If the p-value of the test is less than the significance level then the null hypothesis will be rejected.

Compute the p-value for the two-tailed test as follows:

 [tex]p-value=P(Z>2)\\=1-P(Z<2)\\=1-0.97725\\=0.02275\\\approx 0.023[/tex]

*Use a z-table for the probability.

The p-value of the test is 0.023.

The sum of the measures of the angles of a triangle is 180. The sum of the measures of the second and third angles is five times the measure of the first angle. The third angle is 14 more than the second. Let x, y, and z represent the measures of the first, second, and third angles, respectively. Find the measures of the three angles.

Answers

Answer:

[tex]x=30\\y=68\\z=82[/tex]

Step-by-step explanation:

x = measure of the first angle

y = measure of the second angle

z = measure of the third angle

The sum of the measures of the second and third (y+z) is five times the measure of the first angle (=5x)

[tex]y+z=5x[/tex]

The third angle is 14 more than the second

[tex]z=y+14[/tex]

And remember that the sum of these three angles must be equal to 180.

[tex]x+y+z=180[/tex]

Let's take these equations

[tex]y+z=5x\\z=y+14\\x+y+z=180[/tex]

If you take a look at the first equation, we have y+z = 5x and we have y+z in the third equation as well, we can replace that....

[tex]x+y+z=180\\x+(y+z)=180\\x+(5x)=180[/tex]

Distribute the + sign

[tex]x+5x=180[/tex]

Combine like terms;

[tex]6x=180[/tex]

Divide by 6.

[tex]x=\frac{180}{6}\\ x=30[/tex]

We have now defined that the measure of the first angle is 30º.

Let's take another equation... for example [tex]z=y+14[/tex]

I'm going to take this one because if I replace x and z in the third equation, all I'll have left will be y.

[tex]x+y+z=180\\30+y+(y+14)=180[/tex]

Distribute the + sign and Combine like terms;

[tex]30+y+y+14=180\\44+2y=180\\[/tex]

Subtract 44 to isolate 2y.

[tex]2y=180-44\\2y=136[/tex]

Now divide by 2.

[tex]y=\frac{136}{2}\\ y=68[/tex]

We already have the value of x and y. Once again, replacing this in the third equation will leave us with z to solve for.

[tex]x+y+z=180\\30+68+z=180\\98+z=180\\z=180-98\\z=82[/tex]

The circle graph shows how Spencer spent his money in the month of July.

A circle graph representing Spencers expenses. 27 percent is clothing, 11 percent is Gasoline, 44 percent is Food and 18 percent is Entertainment.

Part A
If Spencer spent a total of $704.00 in the month of July, which is the best estimate for the amount of money he spent on clothing?
$70.00
$140.00
$210.00
$280.00
00:00

Part B
Which is the best estimate for the amount of money he spent on entertainment?
$140.00
$35.00
$105.00
$160.00

Answers

Answer:

$190.08

Step-by-step explanation:

Take 27% of the total $704 spent in July:

0.27($704) = $190.08

He spent an estimated $190.08 on clothing in July.

Answer:

Step-by-step explanation:

I THINK 140

what is this phrase in numerical expression

triple the sum of seventeen and ten

pls help

Answers

Answer: so you would do 17 plus ten which is 27 so triple 3 so your answer is 27^3

Step-by-step explanation:

sum so your adding plus you need the exponent which is times 3

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