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3 years ago

Find the circumference of a circle with a radius of 2.5 cm

Mathematics

1 answer:

solmaris [256]3 years ago

8 0

C=2*pi*r
2*3.141592654*2.5
Answer: 15.7 cm

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Choose the equation of the vertical line passing through point (1,-1)

astraxan [27]

If the line is vertical, then all of the point on the line have the same x-coordinate. In this case the x-coordinate is 1, so x=1.

4 0

4 years ago

Suppose a sample of 100 families of four vacationing at Niagara Falls resulted in sample mean of $282.45 spent per day and a sam

Juli2301 [7.4K]

Given Information:

Mean = μ = $282.45

Standard deviation = σ = $64.50

Sample size = n = 100

Confidence level = 95%

Required Information:

95% Confidence interval = ?

Answer:

95% Confidence interval = ($269.81, $295.09)

Step-by-step explanation:

We are given a Normal Distribution, which is a continuous probability distribution and is symmetrical around the mean. The shape of this distribution is like a bell curve and most of the data is clustered around the mean. The area under this bell shaped curve represents the probability.

What is Confidence Interval?

The confidence interval represents an interval that we can guarantee that the target variable will be within this interval for a given confidence level.

The confidence interval is given by

$CI = \bar{x} \pm MoE\\$

Where $\bar{x}$ is the mean and MoE is the margin of error given by

$MoE = z_{\alpha/2}(\frac{\sigma}{\sqrt{n} } ) \\$

Where σ is the standard deviation, n is the sample size and $z_{\alpha/2}$ is the z-score corresponding to 95% confidence level.

$z_{\alpha/2} = 1 - 0.95 = 0.05/2 = 0.025\\\\z_{0.025} = 1.96$

$MoE = 1.96\cdot \frac{64.50}{\sqrt{100} } \\\\MoE = 1.96\cdot 6.45\\\\MoE = 12.64\\$

Finally, the confidence interval is

$CI = \bar{x} \pm MoE\\\\CI = 282.45 \pm 12.64\\\\CI = 282.45 - 12.64 \: and \: 282.45 + 12.64\\\\CI = \$269.81 \: and \:\:\$295.09\\$

Therefore, we are 95% sure that the true population mean amount spent per day by a family of four visiting Niagara Falls is within the interval of ($269.81, $295.09)

3 0

3 years ago

Solve y=3bx-7x for x

irina [24]

Y = 3bx - 7x
y = x(3b - 7)

Divide each side by 3b - 7 (assume that it is not zero).
$\frac{y}{3b-7} =x$

Answer:
$x= \frac{y}{3b-7}$

6 0

3 years ago

CAN SOMEONE PLS HELP ME I WILL MARK U BRAINLIEST

sukhopar [10]

Answer:

$x \geqslant 1$

Step-by-step explanation:

The expression in the square root should be greater than or equal to zero, because square root of a negative number does not give a real number.

$x - 1 \geqslant 0 \\ x \geqslant 1$

6 0

3 years ago

Read 2 more answers

Rewrite the equation 8x + 6x^2 -7=x^2 in standard form and identify a, b, and c.

Vladimir79 [104]

Answer:

$5x^2+8x-7=0\\a=5\\b=8\\c=-7$

Step-by-step explanation:

The standard form of a quadratic is $ax^2+bx+c=0$ . You need to subtract the x^2 from the right to set the quadratic equal to 0. Then a,b, and c are equal to the values of the coefficients in front of the terms.

If this helped, a brainliest would be greatly appreciated!

6 0

3 years ago