The table shows some information about the lifetimes, t, in hours, of some lightbulbs.

Lifetime Frequency
25 < t ≤ 50 76
50 < t ≤ 100 33
100 < t≤ 150 67
150 < t ≤ 200 28
200 < t ≤ 250 0
250 < t ≤ 300 82
300 < t≤ 350 36

Estimate the mean lifetime of a bulb.
Give your answer rounded to 2 DP.
Plz i need help with this answer quick plzzz

Answers

Answer 1

The mean lifetime of a bulb is 130.82

The table is given as:

Lifetime           Frequency

25 < t ≤ 50       76

50 < t ≤ 100      33

100 < t≤ 150      67

150 < t ≤ 200    28

200 < t ≤ 250    0

250 < t ≤ 300    82

300 < t≤ 350     36

Next, we calculate the mean of the intervals by:

[tex]x = \frac{x_1 + x_2}{2}[/tex]

For interval 25 < t ≤ 50, we have:

[tex]t = \frac{25 + 50}{2} = 37.5[/tex]

For interval 50 < t ≤ 100, we have:

[tex]t = \frac{50 + 100}{2} = 75[/tex]

Using the above formula, we have the new table to be:

Lifetime           Frequency

37.5                      76

75                      33

125                      67

175                      28

225                      0

275                      82

325                      36

The mean is then calculated as:

[tex]\bar x = \frac{\sum fx}{\sum f}[/tex]

So, we have:

[tex]\bar x = \frac{37.5 * 76 + 75* 33 + 125 * 67 + 175 *28 + 225*0 + 275* 82 + 325 *3}{76 + 33 + 67 + 28 + 0 + 82 + 36}[/tex]

Simplify

[tex]\bar x = \frac{42125}{322}[/tex]

Divide

[tex]\bar x = 130.82[/tex]

Hence, the mean lifetime of a bulb is 130.82

Read more about mean at:

https://brainly.com/question/14532771


Related Questions

Which shows 0.124 in expanded form? A. ( 1 × 1 10 ) + ( 2 × 1 100 ) + ( 4 × 1 1000 ) B. 1 + ( 2 × 1 100 ) + ( 4 × 1 1000 ) C. 1 + ( 2 × 1 10 ) + ( 4 × 1 100 ) D. ( 1 × 1 10 ) + ( 20 × 1 100 ) + ( 400 × 1 1000

Answers

Answer:

A. ( 1 × 1 / 10 ) + ( 2 × 1 / 100 ) + ( 4 × 1 / 1000 )

Step-by-step explanation:

A number is written in expanded form if it shows the sum of the values of the individual digits that make up the number.

To write 0.124 in expanded form, follow these steps:

(i) Take the digits one after the other and multiply it by its value depending on its place.

Taking the first digit - 0

The value is 0 unit, where a unit is 1

Now multiply 0 by 1

=> 0 x 1

=> 0

Taking the second digit - 1

The value is 1 tenth, where a tenth is 1 / 10

Now multiply 1 by 1 / 10

=> 1 x 1 / 10

Taking the third digit - 2

The value is 2 hundredth, where a hundredth is 1 / 100

Now multiply 2 by 1 / 100

=> 2 x 1 / 100

Taking the fourth digit - 4

The value is 4 thousandth, where a thousandth is 1 / 1000

Now multiply 4 by 1 / 1000

=> 4 x 1 / 1000

(ii) Add the results obtained in (i) above

=> (0 x 1) + ( 1 x 1 / 10) + (2 x 1 / 100) + ( 4 x 1 / 1000)

=> ( 1 x 1 / 10) + (2 x 1 / 100) + ( 4 x 1 / 1000)

Therefore,

0.124 in expanded form is  ( 1 × 1 / 10 ) + ( 2 × 1 / 100 ) + ( 4 × 1 / 1000 )

Solve for the length of BC. B X A 32 13 С Your answer​

Answers

Answer:

Step-by-step explanation:

take 32 degree as reference angle

using sine rule

sin 32=opposite/hypotenuse

0.52=x/13

0.52*13=x

6.76=x

ifu={12345678},a={1234},b={5678},then find (a union b)`​

Answers

Step-by-step explanation:

A union b is 12345678

So is prime then is empty set

How many bows can you make from 3 and 2/3 meters of ribbon if 1/4 of a meter of ribbon makes one bow

Answers

Answer:

14

Step-by-step explanation:

(11/3)/(1/4)=14 2/3 which means you can make 14 complete bows

Medidas de tendencia central

Answers

Answer:

uhh hell? What does that mean?

Step-by-step explanation:

Which inequality is represented by the graph below? Check all that apply. Ox>9 Ox​

Answers

Answer:

The correct answers are [tex]x < 9[/tex] and any rational number less than 9.

Step-by-step explanation:

Since the inequality represented in the number line has the arrow going towards the left, and has a open/not highlighted circle on 9, that means the inequality represented by the number line is [tex]x < 9[/tex], which means the exact same as any rational number less than 9, so those two choices are the correct answer.

X < 9 and any rational number less than 9

match the graph shown with one of the following equations
A. y=x+2
B. y=-x-2
C. y=x-2
D. y=-x+2
E. y=-x​

Answers

Answer:

A

Step-by-step explanation:

We need to find the correct options which represents the given equation . We can try it out by eliminating the given options , as

Since the graph Intersects the y axis above the origin ,the value of constant is > 0 .

So , option A , and D are preferred choices .

Now the slope of the line is (-1) in option D and 1 in A . Since the graph is in 1st quadrant, so its slope will be positive .

Option A is the correct option . ✔️

Option A is correct answer .

If you spend $20 each week, how much would you have then?

Answers

Answer:

not enough information but i would say 0

Step-by-step explanation:

step by step

Answer:

You would need the amount of money you started with to find the answer to this question.

-61=-3(1-5p)+4(-8-7p)

Answers

Answer: hello! have a good day! :)))

P = 2

What is 12% of 125? Round each answer to the nearest WHOLE number.

Answers

Answer:

10

Step-by-step explanation:

Answer: 15

you do the whole number (125) times the percentage in decimal for (.12)

so its 125 x 0.12 = 15

-2/5 -( -9/15) ?
A -2/5+9/15=3/15
B -9/15-2/5=-1
C -9/15+2/5=-1/5
D 2/5 + 9/15=1

Pls help

Answers

Answer:

the answer is

C)-9/15-2/5=-1/5

A
- (-) = +
-2/5 -(-9/15)= - 2/5 + (9/15)

what is going on
I am confused ​

Answers

?????? what do you mean

Answer:

What do you mean?

Step-by-step explanation:

I would suggest adding more info

A triangular pyramid has a base shaped like an equilateral triangle. The legs of the equilateral triangle are all 6 yards long, and the height of the equilateral triangle is 5.2 yards. The pyramid's slant height is 7 yards. What is its surface area?

Answers

Answer:

78.6 sq. yards

Step-by-step explanation:

SA = (½×6×5.2)+(3×½×6×7)

= 15.6 + 63 = 78.6 sq. yards

What is the area of the polygon?

Answers

Answer:

[tex]154m^{2}[/tex]

Step-by-step explanation:

8 · 7 = 56m (horizontal rectangle shape) the width was given by subtracting the total of the width (23m) minus (16m).

5 · 8 = 40m (square shape) Subtract 8m - 3m = 5m.

6 · 8 = 48m (square shape to the left of the polygon)

2 · 5 = 10m  (small rectangle shape bottom left) 8 - 6 = 2 for the length and 5 for the width by 8 - 3 = 5

56m + 40m + 48m + 10m = 154 [tex]m^{2}[/tex]

What is the area of the figure? Round to the nearest tenth.
10 m
5 m
4 m

A 20.0 m2
B. 40.0 m2
O c. 45.0 m2
OD 50.0 m2

Answers

i believe the answer is c sorry if i’m wrong

The parallelogram shown below has an area of 140 units² .

Answers

Answer:

Step-by-step explanation:

140 = b * h

140 = b * 10

14 = b

Estimate the line of best fit using two points on the line. (8, 80) 100 90 80 70 60 50 40 30 20 10 (2.20) 10 O A. y= 2x O B. y = 2x + 10 O c. y= 10x+ 2 OD. y= 10x​

Answers

Answer:

[tex]y = 10x[/tex]

Step-by-step explanation:

Given

The attached plot

Required

The line of the best fit using [tex](8,80)[/tex] and [tex](2,20)[/tex]

We have:

[tex](x_1,y_1) = (8,80)[/tex]

[tex](x_2,y_2) = (2,20)[/tex]

Calculate slope (m)

[tex]m = \frac{y_2 - y_1}{x_2 - x_1}[/tex]

[tex]m = \frac{20 - 80}{2- 8}[/tex]

[tex]m = \frac{-60}{-6}[/tex]

[tex]m = 10[/tex]

The equation is then calculated using:

[tex]y = m(x - x_1) + y_1[/tex]

[tex]y = 10(x - 8) + 80[/tex]

Expand

[tex]y = 10x - 80 + 80[/tex]

[tex]y = 10x[/tex]

PLEASE HELP 7TH GRADE MATH
BRAINLIEST-SHOWS WORK
PLEASE HELP
ANSWER 1 OR MORE AN WILL MARK BRAINLIEST 1 OR MORE

Answers

Answer:

well it cant start off in the middle of the graph most graphs you start from the very beginning like lets just say we start at 11 and go all the way to the end so kinda like a straight line

Step-by-step explanation:

Simplify this expression by distributing: (p - 3)6.

Answers

Answer:

6p-18

Step-by-step explanation:

Answer:

6p -18

Step-by-step explanation:

(p - 3)6

Distribute

6*p - 6*3

6p -18

what is communication​

Answers

Answer:

An interaction that you do verbally or physically to let someone know something.

it either

the imparting or exchanging of information or news

or

means of sending or recieving information, such as phone lines or computers

The population of a small town in Alberta was 2000. The population
increased by 13% one year and by 7% the next year. What was the town's population after the 2 years?

Answers

Answer:
First year = 2260
Second year = 2140
Total year = 2,400

PLEASE HELP ME IT'S MY LAST GRADE​

Answers

Answer:

c

Step-by-step explanation:

Answer:

C

Step-by-step explanation:

PLSSS I NEED HELP NOW!!!! Each square of ABCD is equal to 4, M is the midpoint of AB, and N is the midpoint of AD. What is the area of MNC?

Answers

Answer:

2 Units

Step-by-step explanation:

1) The shape is a square shaped like a box

2) The interior Area is equal to 4

3) M is the midpoint of AB

4) N is the Midpoint of AD

5) Connecting angle MNC would create a triangle inside of the square

6) This would make the area of the triangle MNC 2 units

PLEASE HELP!! IF YOU ANSWER I WILL GIVE YOU BRAINLIST
At 5:00 a.m., the temperature outside was 6°F below zero. By 12:00 p.m., it rose by 9°F. At 7:00 p.m., the temperature dropped by 5°F. What was the evening temperature?


A.

–20°F


B.

20°F


C.

8°F


D.

-2°F

Answers

Answer:

D.

(The only option that makes sense is D. but I came up with 10°F when I did the math)

~ LadyBrain

If 35% of a number is 21 and 90% of the same number is 54, find 55% of that number.​

Answers

the answer is on the picture

x>-2

Wyatt wants to spend no more than $25 at the grocery store. He bought a

pizza for $7.55 and a cake for $11.02 (including tax). Choose the inequality

that he can use to find how much money he can still spend.

Answers

Answer:

he spent $18.57 and he can spend $7.43 more

The solution is, he can still spend no more than $6.43.

What is inequality?

An inequality is a relation which makes a non-equal comparison between two numbers or mathematical expressions.

here, we have,

given that,

Wyatt wants to spend no more than $25 at the grocery store.

He bought a pizza for $7.55 and a cake for $11.02 (including tax).

now, we have to find the inequality that he can use to find how much money he can still spend.

let, we would spend = x

now, we have,

He bought a pizza for $7.55 and a cake for $11.02

so, he had = $ x - ( 7.55 + 11.02)

we have,

x ≥ 25

so, he can still spend ≥ 25 -  ( 7.55 + 11.02)

or, he can still spend ≥ 6.43

i.e.  he can still spend no more than $6.43

Hence, The solution is, he can still spend no more than $6.43.

To learn more on inequality click:

brainly.com/question/24853349

#SPJ2

lect the correct answer.
These temperatures were recorded in International Falls, Minnesota, on four consecutive days:

day 1: -10°F
day 2: -13°F
day 3: -8°F
day 4: -11°F

On which day was the temperature farthest from 0°F ?

A.
day 1
B.
day 2
C.
day 3
D.
day 4

Answers

Answer:

b. day 2 is the farthest from 0

The day the tempura was the farthest was on day 4

Can someone please help?

Answers

It’s the third one. .

[tex]9 \times \frac{1}{4} = \frac{9}{4} [/tex]✅

Step-by-step explanation:

Option A

[tex]5 \times \frac{1}{2} = \frac{1}{10} \\ ⇢  \frac{5}{2} ≠ \frac{1}{10} [/tex]

Option B

[tex]4 \times \frac{1}{3} = \frac{4}{12} \\ ⇢ \frac{4}{3} ≠ \frac{4}{12} [/tex]

Option C

[tex]9 \times \frac{1}{4} = \frac{9}{4} \\ ⇢ \frac{9}{4} = \frac{9}{4} [/tex]

Option D

[tex]8 \times \frac{1}{ 5} = \frac{9}{5} \\ ⇢ \frac{8}{5} ≠ \frac{9}{5} [/tex]

Hence, option C is correct.

[tex]\circ \: \: { \underline{ \boxed{ \sf{ \color{green}{Happy\:learning.}}}}}∘[/tex]

The weights of running shoes are normally distributed with an unknown population mean and standard deviation. If a random sample of 31 running shoes is taken to estimate the mean shoe weight, what t-score should be used to find a 98% confidence interval estimate for the population mean

Answers

Answer:

The t-score is t = 2.457.

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 = 31 - 1 = 30

98% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 30 degrees of freedom(y-axis) and a one-tailed confidence level of [tex]1 - \frac{1 - 0.98}{2} = 0.99[/tex]. So we have T = 2.457.

The t-score is t = 2.457.

How much does $3,000 earn in six months at an interest rate of 4 compounded quarterly?

Answers

Answer:

The final balance is ₹4,926.8.

The total compound interest is ₹3,926.8.

The amount of money that was earned in six months with an interest rate of 4 compounded quarterly will be $3184.6.

What is compound interest?

A loan or deposit's interest is computed using the starting principle and the interest payments from the ago decade as compound interest.

We know that the compound interest is given as

[tex]\rm A = P \left (1 + \dfrac{r}{n} \right ) ^{nt}[/tex]

Where A is the amount, P is the initial amount, r is the rate of interest, and t is the number of years.

The principal amount of $3,000 was earned in six months at an interest rate of 4 compounded quarterly. Then the value of n will be 4. Then we have

[tex]A = 3000 \left (1 + \dfrac{0.04}{4} \right )^6[/tex]

Simplify the equation, then we have

A = 3000 (1.01)⁶

A = 3000 x 1.062

A = $3184.6

The amount of money that was earned in six months with an interest rate of 4 compounded quarterly will be $3184.6.

More about the compound interest link is given below.

https://brainly.com/question/25857212

#SPJ2

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