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Ray Of Light [21]

2 years ago

12

In a study of 225 adults, the average heart rate was 72 beats per minute. Assume the population of heart rates is known to be ap

proximately normal, with a standard
deviation of 10 beats per minute. What does a margin of error of 1.1 for the 90% confidence interval of the average beats per minute mean?

2 answers:

irinina [24]2 years ago

6 0

Answer:

it means that if the survey is repeated there is a 90% chance that the average heart rate is 72 bears per minute with plus or minus 1.1 %

Step-by-step explanation:

Confidence interval explains to what percentage will the result be true if the experiment is repeated multiple times

Margin of error tells the range of accuracy if the result is true when the experiment is repeated multiple times.

Inessa [10]2 years ago

5 0

I think it’s like the root

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We flip a fair coin five times. For every heads you pay me $1 and for every tails I pay you $1. Let X denote the my net winning

TEA [102]

Answer:

The probability mass of X is 0.03

Step-by-step explanation:

If we set the winning requirement of your heads and my tails then the occurring possibility of both is 1/2 or 0.5.

Hence let us make a graph and use the figures to calculate the all the probabilities of you getting a heads.

Where X represents the number of dollars won during the flip of the coin, probability of heads represent the chances of occurrence of the value and of winning the dollars.

The probability of winning start to drop as the winning amount increases.

X 0 1 2 3 4 5

Probability of Heads 0 0.50 0.25 0.13 0.06 0.03

8 0

2 years ago

A flat circular plate has the shape of the region x squared plus y squared less than or equals 1x2+y2≤1. the plate, including t

vredina [299]

You're looking for the extreme values of $x^2+3y^2+13x$ subject to the constraint $x^2+y^2\le1$ .

The target function has partial derivatives (set equal to 0)

$\dfrac{\partial(x^2+3y^2+13x)}{\partial x}=2x+13=0\implies x=-\dfrac{13}2$

$\dfrac{\partial(x^2+3y^2+13x)}{\partial y}=6y=0\implies y=0$

so there is only one critical point at $\left(-\dfrac{13}2,0\right)$ . But this point does not fall in the region $x^2+y^2\le1$ . There are no extreme values in the region of interest, so we check the boundary.

Parameterize the boundary of $x^2+y^2\le1$ by

$x=\cos u$

$y=\sin u$

with $0\le u$ . Then $t(x,y)$ can be considered a function of $u$ alone:

$t(x,y)=t(\cos u,\sin u)=T(u)$

$T(u)=\cos^2u+3\sin^2u+13\cos u$

$T(u)=3+13\cos u-2\cos^2u$

$T(u)$ has critical points where $T'(u)=0$ :

$T'(u)=-13\sin u+4\sin u\cos u=\sin u(4\cos u-13)=0$

$(1)\quad\sin u=0\implies u=0,u=\pi$

$(2)\quad4\cos u-13=0\implies\cos u=\dfrac{13}4$

but $|\cos u|\le1$ for all $u$ , so this case yields nothing important.

At these critical points, we have temperatures of

$T(0)=14$

$T(\pi)=-12$

so the plate is hottest at (1, 0) with a temperature of 14 (degrees?) and coldest at (-1, 0) with a temp of -12.

4 0

2 years ago

A rectangle has height and width changing in such a way that the area remains constant 2 square feet. At the instant the height

hichkok12 [17]

Answer:

$\frac{1}{3}$ ft/min is the rate of changing of width

Step-by-step explanation:

Given -

The area always remain constant i.2 2 square feet.

Height of the rectangle = 2 feet

Rate of changing of height = 6 feet per minute

Since area is constant

2 sq ft = (2 * 6) ft/min * 1 * x ft/min

x = $\frac{1}{3}$ ft/min

4 0

2 years ago

What is 1 4/7 as a improper fraction

Serhud [2]

Hello there,

To write an improper fraction you will have to divide whole number by denominator than add the numerator...

7 * 1 = 7

7 + 4 = 11

The denominator stays the same...

11/7

Answer: 11/7

Hope I helped!!

-Char

3 0

2 years ago

Read 2 more answers

Solve the radical equation. square root 6n-11= n – 3 Which solution is extraneous? A.)2

Anvisha [2.4K]

ANSWER

D) 10

EXPLANATION

We want to solve the radical equation,

$\sqrt{6n - 11} = n - 3$

Square both sides,

$6n - 11 = (n - 3) ^{2}$

Expand brackets on right hand side,

$6n - 11 = {n}^{2} - 6n + 9$

Rewrite in general quadratic equation form,

${n}^{2} - 12n + 20 = 0$

Factor to obtain,

$(n - 2)(n - 10) = 0$

Apply the zero product principle to get,

$n = 2 \: or \: n = 10$

We put n=2 into the equation to get,

$\sqrt{6(2) - 11} = 2 - 3$

$1 = - 1$

This statement is false, hence 2 is an extraneous solution

We put n=10, to get

$\sqrt{6(10) - 11} = 10 - 3$

$\sqrt{49} = 7$

$7 = 7$

This is true, hence the only solution is
$n = 10$

3 0

2 years ago

Read 2 more answers