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3 years ago

True or false: x+3 is an equation.

Mathematics

2 answers:

skad [1K]3 years ago

6 0

Answer: true

Step-by-step explanation:

Salsk061 [2.6K]3 years ago

3 0

Answer:

True

This is called an unknown equation where the first number is unknown

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1. A manufacturer of a printer determines that the mean number of days before a cartridge runs out of ink is 75 days, with a sta

satela [25.4K]

Answer:

$P(X$

And we can find this probability using the normal standard table or excel:

$P(z$

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the number of days before cartridge runs out of a population, and for this case we know the distribution for X is given by:

$X \sim N(75,6)$

Where $\mu=75$ and $\sigma=6$

We are interested on this probability

$P(X$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X$

And we can find this probability using the normal standard table or excel:

$P(z$

8 0

3 years ago

What is the EQUATION of the line PERPENDICULAR to y=-2x+5 and passing through the point (0,2)?

KonstantinChe [14]

$▪▪▪▪▪▪▪▪▪▪▪▪▪ {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪$

The required equation is ~

$\boxed{ \sf{y = \frac{x}{2} + 2 }}$

$\large \boxed{ \mathfrak{Step\:\: By\:\:Step\:\:Explanation}}$

Let's find the slope of given line ~

$y = - 2x + 5$

comparing it with general slope - intercept form of line (y = mx + c) we get, m = -2 (that is slope of the line)

let the slope of the required line be n

And, now since the required line Is perpendicular to the given line. the product of their slopes is -1

that is ~

$- 2 \times n = - 1$

$n = \dfrac{ - 1}{ - 2}$

$n = \dfrac{1}{2}$

slope of required line is ~ 1/2

now, let's use the point - slope form of line to find the equation of required (perpendicular) line (using point (0 , 2) ~

that is ~

$y - y_1 = m(x - x_ 1)$

here, m = slope ~

$y - 2 = \dfrac{1}{2} (x - 0)$

$y - 2 = \dfrac{x}{2}$

$y = \dfrac{x}{2} + 2$

I hope it helps ~

4 0

3 years ago

The formula T = 1/f relates the period of a sound wave T to its frequency f. Solve this formula for f.

Liono4ka [1.6K]

$T=\frac{1}{f}$

$multiply \space\ both \space\ sides \space\ by \space\ f$

$Tf=1$

$divide \space\ both \space\ sides \space\ by \space\ T$

$f=\frac{1}{T}$

7 0

4 years ago

Read 2 more answers

A random sample of 9 wheels of cheese yielded the following weights in pounds has a sample mean of 20.90 and a sample variance o

Ronch [10]

Answer:

$2.002 \leq \sigma^2 \leq 11.365$

Step-by-step explanation:

1) Data given and notation

s represent the sample standard deviation

$s^2$ represent the sample variance

n=9 the sample size

Confidence=90% or 0.90

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi Square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case we need to find the sample standard deviation with the following formula:

$s=sqrt{\frac{\sum_{i=1}^9 (x_i -\bar x)^2}{n-1}}
The sample variance given was [tex]s^2=3.45$

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=9-1=8$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical values.