The lifetime of a certain brand of battery is known to have a standard deviation of 9 hours. Suppose that a random sample of 90 such batteries has a mean lifetime of 38.9 hours. Based on this sample, find a 90% confidence interval for the true mean lifetime of all batteries of this brand.

Answers

Answer 1

Answer:

lower limit : 36.44

upper limit : 39.56

Step-by-step explanation:

Given :

s = 9

n = 90

x = 38.9

Alpha, α = 0.10

∴ [tex]$z_{\alpha/2}=z_{0.05} = 1.645$[/tex]

The confidence interval is :

[tex]$=x \pm\left(z_{\alpha /2} \times \frac{s}{\sqrt{n}}\right)$[/tex]

[tex]$=38.9 \pm\left(1.645 \times \frac{9}{\sqrt{90}}\right)$[/tex]

[tex]$=38.9 \pm 1.56$[/tex]

[tex]$=(36.44, 39.56)$[/tex]

Therefore,

lower limit : 36.44

upper limit : 39.56


Related Questions

During a sale, a store offered a 15% discount on a couch that originally sold
for $800. After the sale, the discounted price of the couch was marked up by
15%. What was the price of the couch after the markup? Round to the nearest
cent.

Answers

Answer:

t think the answer is 1040.

Paul rides his bike for 2 hours at a constant rate of 20 mph. He then bikes for 3 hours at a constant rate of 25 mph. How far did Paul travel in the 5 hours?
A. 15 mi.
B. 52 mi.
C. 115 mi.
D. 165 mi.

Answers

In 5 hours Paul travelled 115 miles

Please help a girl out, math is not my forte

Answers

Answer:

80 ft²

Step-by-step explanation:

You are given the formula

a = (1/2)bh

Just plug in the base and height, then multiply

a = (1/2) * 8 *20

a = (1/2) * 160

a = 80 ft²

Answer:

80 [tex]ft^{2}[/tex]

Step-by-step explanation:

Area = [tex]\frac{1}{2} bh[/tex]

Area = [tex]\frac{1}{2}[/tex] 8 · 20

Area = [tex]\frac{1}{2}[/tex] 160

Area = 80 [tex]ft^{2}[/tex]

Activity IB. FIND ME!
Find the area of each circle. Use = 3.14
3.
1.
2.
om
13cm
19in.
5.
33cm
25cm
yan paki sagot​

Answers

1 “113.04m²”
2 “530.66m²”
3 “1133.54in²”
4 “854.865cm²”
5 “1962.5cm²”
Hope it helps :)

What value of x is in the solution set of 8x – 6 > 12 + 2x? ​

Answers

Answer:

x  > 3

Step-by-step explanation:

[tex]8x - 6 > 12 + 2x\\\\8x - 6 + 6 > 12 + 6 + 2x\\\\8x > 18 + 2x\\\\8x - 2x > 18 +2x-2x\\\\6x > 18\\\\\frac{6x>18}{6}\\\\\boxed{x > 3}[/tex]

Any value that is greater than 3 would be in the solution set for the inequality.

Hope this helps.

Answer:

x > 3

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Equality Properties

Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtraction Property of Equality

Algebra I

Terms/Coefficients

Step-by-step explanation:

Step 1: Define

Identify

8x - 6 > 12 + 2x

Step 2: Solve for x

[Subtraction Property of Equality] Subtract 2x on both sides:                      6x - 6 > 12[Addition Property of Equality] Add 6 on both sides:                                     6x > 18[Division Property of Equality] Divide 6 on both sides:                                  x > 3

find the missing angle measures by examining the angle relationships first

m m m

Answers

∠ b = 43° — — { Vertical opp. angles]

Now, see 43 and a are together compromising the linear pair so,

= 43 + a = 180°

= a = 180 - 43

= a = 137

Like b, similarly here also a = c = 137° {Vertical opp. angles}

Faith has some coins in two different pockets. The shaded areas in the diagrams below represent the value of the coins in each pocket.

What is the total value, in dollars, of the coins that Faith has in both pockets?​

Answers

Answer:

$3.05

Step-by-step explanation:

Each box is $0.05

The shades boxes represent the value of coin in each pocket :

Number of shaded boxes on the left = 24

Value of coins in left pocket = 24 * $0.05 = $1.2

Number of shaded boxes on the right = 37

Value of coins in right pocket = 37 * $0.05 = $1.85

Tital value if coins :

$1.85 + $1.2

= $3.05

NEED HELP ON THIS ASAP PLZ!!​

Answers

Answer:

cos0 = 6.8556546i/23 or sqrt-47/23

Step-by-step explanation:

hypotenuse is 23, opposite is 24

we have to find the adjacent using the pythagorean theorem

24^2 + b^2 = 23^2

576+b^2=529

subtract

b^2=-47

b=sqrt-47

sqrt of -47 is 6.8556546i, there is an i since it is the square root of a negative

cos = adjacent/hypotenuse

A rectangle has a length of 16
inches and a width of 6 inches. A similar rectangle has a length of 24 inches. What is the width of the similar rectangle?

Answers

Answer:

9 inches

Step-by-step explanation:

Given

Let;

[tex]L = Length; W= Width[/tex]

So:

[tex]L_1=16in; W_1 = 6in[/tex]

[tex]L_2 = 24[/tex]

Required

Determine [tex]W_2[/tex]

To do this, we make use of the following equivalent ratios

[tex]L_1 : W_1 = L_2:W_2[/tex]

This gives

[tex]16 : 6= 24:W_2[/tex]

Express as fraction

[tex]\frac{6}{16}= \frac{W_2}{24}[/tex]

Multiply by 24

[tex]W_2 = 24 * \frac{6}{16}[/tex]

[tex]W_2 = 9[/tex]

The slope-intercept form of the equation of a line that passes through point (–3, 8) is y = –y minus 3 equals negative StartFraction 2 Over 3 EndFraction left-parenthesis x plus 8 right-parenthesis.x + 6. What is the point-slope form of the equation for this line?

y – 3 = –StartFraction 8 Over 5 EndFraction x plus StartFraction 2 Over 3 EndFraction equals StartFraction one-half EndFraction minus StartFraction 1 Over 5 EndFraction x.(x + 8)
y + 3 = –y plus 3 equals negative StartFraction 2 Over 3 EndFraction left-parenthesis x minus 8 right-parenthesis.(x – 8)
y + 8 = –y plus 8 equals negative StartFraction 2 Over 3 EndFraction left-parenthesis x minus 3 right-parenthesis.(x – 3)
y – 8 = –y minus 8 equals negative StartFraction 2 Over 3 EndFraction left-parenthesis x plus 3 right-parenthesis.(x + 3)

Answers

D. y – 8 = –y minus 8 equals negative Start Fraction 2 Over 3 End Fraction left-parenthesis x plus 3 right-parenthesis.(x + 3)

Step-by-step explanation:

I took the test and got it right

Answer:

its D just did the test on edge

Step-by-step explanation:

Which expression give the best estimate of 45 percent of 76

Answers

Answer:

a. One-fourth (80)

b. One-fifth (80)

c. One-half (80)

d.  One-ninth (80)

the answer is C.

Step-by-step explanation:

Estimate .45 to .50 which is 1/2

= 1/2 (80)

hope this helps!

Solve the inequality 5u≤8u−21 and write the solution in interval notation

Answers

Answer:

Step-by-step explanation:

[tex]5u\leq 8u-21[/tex]

Subtract 8u from both sides

[tex]-3u\leq -21[/tex]

Divide by -3 on both sides

[tex]u\geq 7[/tex]

Interval notation: [greater/less than or equal to], (greater or equal to)

[7,∞)

The solution to the inequality is u ≥ 7, which means that u is greater than or equal to 7. In interval notation [ 7, ∞).

What is inequality?

In mathematics, an inequality is a remark that two values or expressions are not equal. An inequality uses one of the comparison symbols: "<" (less than), ">" (greater than), "≤" (less than or equal to), "≥" (greater than or equal to), or "≠" (not equal to).

Here,

To solve the inequality 5u ≤ 8u - 21, we can start by isolating u on one side of the inequality. We can do this by subtracting 5u from both sides:

5u ≤ 8u - 21

-3u ≤ -21

Divide both sides by -3. Note that dividing by a negative number will reverse the direction of the inequality:

u ≥ 7

Therefore, the solution to the inequality is u ≥ 7, which means that u is greater than or equal to 7. In interval notation [ 7, ∞).

Learn more about inequality here:

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will give brainly please help now <3

Answers

Answer:

16 ounces/minute

Step-by-step explanation:

1 pound = 16 ounce

60 pound = 960 ounce

1 hour = 60 minute

960/60 = 16

Select the correct answer.
The body of a person who weighs 50 kilograms contains around 2 × 102 grams of sodium chloride. How much sodium chloride is contained in the bodies of 1.8 × 103 people who each weigh 50 kilograms? Represent the answer in scientific notation.
A.
3.6 × 105 grams
B.
1.1 × 101 grams
C.
36 × 105 grams
D.
11 × 101 grams

Answers

Answer:

3.6 x 10⁵ g of sodium chloride

Step-by-step explanation:

Answer:

3.6 x 10⁵ g

Step-by-step explanation:

Hi I needed help with my math homework. can you please help :| .....
Question: c - 1.3 = 6

Answers

Answer:

7.3

Step-by-step explanation:

c- 1.3 = 6

c = 6 + 1.3

c = 7.3

nay it helped u

PLEASE HELP GEOMETRY!!!!!!!! DUE TODAY

What is the measure of

Answers

(D) step by step below

what is the most $ that you can get out of a ATM?

Answers

Answer:

$200

Step-by-step explanation:

Answer:

I think it is 200$

Step-by-step explanation:

By the distributive law, 49 * 17 + 49 * 3 =

Answers

Answer:

980

hope it helps

translate into algebraic expression " the sum of five times m and n​

Answers

Explanation:
"Five times" means
5
(
...
)
,
"the sum of a number, say
x
, and

3
", means"{(x+(-3)}=(x-3)#.
Taking all these together, the reqd. Algebraic Expression turns out to be
5
(
x

3
)
.

2. A set of data consists of the number of years that applicants for foreign service
jobs have studied German and the grades that they received on a proficiency test.
The following regression equation is obtained: = 31.6 + 10.9x, where x represents
the number of years of study and y represents the grade on the test.
a. Identify the predictor and response variables.
b. Interpret the regression equation by interpreting the y-intercept and slope.

Answers

Answer:

Kindly check explanation

Step-by-step explanation:

Given the regression equation :

y = 31.6 + 10.9x

x = the number of years of study ;

y = the grade on the test.

The predicted is y which is also the same as the response variable, hence, the response variable is grade on the test

The predictor variable is x, which is the independent variable, which is the number of years of study.

From. The regression output given ;

The slope which is the Coefficient of the predictor variable is 10.9 which means that for every unit change in number of years of study, the grade on test increases by 10.9

The intercept which is the constant value, 31.6, means, the least a person can get in the get in grade is 31.6 (at x = 0)

is this an example of direct variation? f(x)=2xy

Answers

Answer:

Yes, it is:

Step-by-step explanation:

Given

[tex]f(x) =2xy[/tex]

Required

Determine if it is a direct variation

A direct variation is represented as:

[tex]f(x)\ \alpha\ x[/tex]

Express as equation

[tex]f(x) = kx[/tex]

Compare [tex]f(x) = kx[/tex] to [tex]f(x) =2xy[/tex]

[tex]k = 2y[/tex]

Hence, it is a direct variation

Write the slope-intercept form of the equation of the line through the point (-1,-4) with the slope of 6.

Answers

Answer:

y-y1=m(x-x1)

y+4=6(x+1)

y=6x+2

Last question I need help with an answer not a link

Answers

Answer:

it's toooo complicated

A rectangular field is 0.35 kilometers long and 0.2 kilometers wide. What is the area of the field in square meters?
I need step-by step work?

Answers

Answer : 70 square meter

Area of rectangle = length x width

Here, Area of rectangle = 0.35 x 0.2 = 0.07 square km which is 70 square meter

As answer is required in square meter, you need to convert kilometer into meter.

The area of the rectangular field is 70000 square m if the rectangular field is 0.35 kilometers long and 0.2 kilometers wide.

What is the area of the rectangle?

It is defined as the area occupied by the rectangle in two-dimensional planner geometry.

The area of a rectangle can be calculated using the following formula:

Rectangle area = length x width

Area of rectangle = 0.35x0.2 = 0.07 square km

1 km = 1000 m

1 square km = 1000000 square m

Area of rectangle = 0.07x1000000 square m

Area of rectangle = 70000 square m

Thus, the area of the rectangular field is 70000 square m if the rectangular field is 0.35 kilometers long and 0.2 kilometers wide.

Learn more about the rectangle here:

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Gianna brought seven necklaces for $50.75 and Winnie brought three necklaces for $24.60 who got the better deal

Answers

Gianna paid less per necklace so she got the better deal

Gianna: 50.75 / 7 = 7.25
So she paid $7.25 per necklace
Winnie: 24.60 / 3 = 8.20
So she paid $8.20 per necklace

Why is triangle called an obtuse triangle?
a. It has zero obtuse angles
b. It has 2 obtuse angles
c. It has 1 obtuse angle
d. It has 3 obtuse angles

Which is NOT a polygon?
a. A break
b. A donut
c. A window
d. A stop sign

What do you call a polygon with equal side lengths and angle measures?
a. Vertex
b. Nonconvex
c. Irregular polygon
d. Regular polygon

Tell whether the figure at the right is a polygon. If it is, name it by the number of sides.
a. Not a polygon
b. Polygon - hexagon
c. Polygon - pentagon
d. Polygon - convex

If all the sides and angles in a parallelogram are equal then, which shape is it?
a. Rectangle
b. Triangle
c. Square
d. Rhombus

What do you call a polygon that is both equilateral and equiangular?
a. Segment
b. Irregular polygon
c. Regular polygon
d. Vertices

Which is not represented by the figure shown below?
a. Polygon
b. Parallelogram
c. Quadrilateral
d. Rectangle

How many diagonals must pass outside the figure to classify a polygon as nonconvex?
a. Zero
b. At least one
c. At least two
d. All of them

Which best describes the polygon below?
a. A regular hexagon
b. A convex hexagon
c. An arrow
d. A nonconvex hexagon

Tell whether the figure below is a polygon. If it is, name it by the number of sides.
a. Not a polygon
b. Polygon - octagon
c. Polygon - hexagon
d. Polygon - nonconvex​

Answers

Answer:

An obtuse angle is an angle that measures

more than 90 degrees and less than 180

degrees.

Answer:

answers in explanation...

Step-by-step explanation:

1. is C it has 1 obtuse angle

2.  b. a donut is not a polygon. ( bricks,windows,and stop signs are polygons)

3. d. a regular polygon.

4. ( i cannot do without the image)

5. a. rectangle

6.c. a regular polgony

7.(cannot do without image)

8.b. at least one

9.(cannot do without image)

10. ( cannot do wihtout image)

What are the domain and range of this function?

Answers

Answer: Choice DDomain: all real numbersRange: [tex]y \ge 1[/tex]

===========================================

Explanation:

The domain is the set of allowed x inputs. We can plug in any x value we want as the graph stretches on forever to the left and to the right. There aren't any division by zero errors or any issues like that to worry about, so that's why we don't kick out any x values from the domain.

The domain being all real numbers translates to the interval notation [tex](-\infty, \infty)[/tex] which is basically saying [tex]-\infty < x < \infty[/tex]

-----------------------------------

The range is the set of y outputs possible. The graph shows that y = 1 is the smallest y output, so y = 1 or y can be greater than this.

In short, [tex]y \ge 1[/tex] is the range which converts to the interval notation [tex][1, \infty)[/tex] which is the same as saying [tex]1 \le y < \infty[/tex]

-----------------------------------

Extra info:

The equation of this absolute value function is y = |x|+1

Multiply this please

Answers

Answer:

-70x² + 49x - 63

Step-by-step explanation:

7( -10x² + 7x - 9) =

7( -10x²) + 7(7x) - 7(9) =

-70x² + 49x - 63

If my answer is incorrect, pls correct me!

If you like my answer and explanation, mark me as brainliest!

-Chetan K

You measure 34 textbooks' weights, and find they have a mean weight of 69 ounces. Assume the population standard deviation is 8.2 ounces. Based on this, construct a 95% confidence interval for the true population mean textbook weight. Give your answers as decimals, to two places

Answers

Answer:

The 95% confidence interval for the true population mean textbook weight is between 66.24 and 71.76 ounces.

Step-by-step explanation:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.95}{2} = 0.025[/tex]

Now, we have to find z in the Z-table as such z has a p-value of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.025 = 0.975[/tex], so Z = 1.96.

Now, find the margin of error M as such

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

[tex]M = 1.96\frac{8.2}{\sqrt{34}} = 2.76[/tex]

The lower end of the interval is the sample mean subtracted by M. So it is 69 - 2.76 = 66.24 ounces

The upper end of the interval is the sample mean added to M. So it is 69 + 2.76 = 71.76 ounces.

The 95% confidence interval for the true population mean textbook weight is between 66.24 and 71.76 ounces.

Given f(x)= 17- x2, what is the average rate of change in f(x) over the interval [1, 5)?
O -6
O -1/2
O 1/4
O 1

Answers

-6 because it is yeah so
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