Write the following equation in the general form Ax + By + C = 0. 2x + y = 6

A company is in the business of finding addresses of long-lost friends. The company claims to have a 70% success rate. Suppose t

Galina-37 [17]

Answer:

a) Figure attached

b) $E(X) =\mu= np = 9*0.7=6.3$

$Sd(X) =\sigma= \sqrt{np(1-p)}= \sqrt{9*0.7*(1-0.7)}=1.375$

c) For the case n= 6

$P(X \leq 2) = 0.9891$

For the case n= 5

$P(X \leq 2) = 0.9692$

So then we need at least n=5 or n=6 to satisfy the condition required.

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=9, p=0.7)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

Part a

For this case we can use the following R code:

> x <- seq(0,9,by = 1)

> y <- dbinom(x,9,0.7)

> plot(x,y,main="Histogram",type = "h")

And we can see on the figure attached the solution.

We see that the higher probabilities are from 4 to 9

Part b

The expected value is given by:

$E(X) =\mu= np = 9*0.7=6.3$

The variance is given by:

$Var (X) =\sigma^2= np(1-p) = 9*0.7*(1-0.7)= 1.89$

And the standard deviation is:

$Sd(X) =\sigma= \sqrt{np(1-p)}= \sqrt{9*0.7*(1-0.7)}=1.375$

Part c

First we can find the probability that at least two addresses will be found in the list of 9 that we have like this:

$P(X \geq 2)$

We can use the complement rule and we have:

$P(X \geq 2) = 1-P(X$

We find the indicidual probabilities:

$P(X=0)=(9C0)(0.7)^0 (1-0.7)^{9-0}=0.00001968$

$P(X=1)=(9C1)(0.7)^1 (1-0.7)^{9-1}=0.000413$

$P(X \geq 2) = 1-[0.00001968+0.000413]=0.9996$

If we use the case of n=8 and we find $P(X\leq 2)$ , we got:

$P(X \leq 2) = 0.9987$

For the case n= 7

$P(X \leq 2) = 0.9962$

For the case n= 6

$P(X \leq 2) = 0.9891$

For the case n= 5

$P(X \leq 2) = 0.9692$

So then we need at least n=5 or n=6 to satisfy the condition required.

5 0

2 years ago

The National Institute of Standards and Technology (NIST) supplies "standard materials" whose physical properties are supposed t

Lady bird [3.3K]

Answer:

$10.08-1.64\frac{0.1}{\sqrt{6}}=10.013$

$10.08+1.64\frac{0.1}{\sqrt{6}}=10.147$

So on this case the 90% confidence interval would be given by (10.013;10.147)

Step-by-step explanation:

Previous concepts

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 means 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.

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".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma =0.1$ represent the population standard deviation

n represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (2)

$s=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar X)}{n-1}}$ (3)

The mean calculated for this case is $\bar X=10.08$

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 tabel to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

Now we have everything in order to replace into formula (1):

$10.08-1.64\frac{0.1}{\sqrt{6}}=10.013$

$10.08+1.64\frac{0.1}{\sqrt{6}}=10.147$

So on this case the 90% confidence interval would be given by (10.013;10.147)

5 0

2 years ago

Simplify the expression below. 12b + 86 + 5b 0 25 + b O 25(3b) 25b 3b

Alja [10]

(1): "^-5" was replaced by "^(-5)". 3 more similar replacement(s)

STEP

1

:

Equation at the end of step 1

((25•(b-1))•(c-3))

(((12•(b4))•(c-6))•——————————————————)•((2•5b(-5))•c)

((15•(b3))•(c4))

STEP

2

:

Equation at the end of step

2

:

((25•(b-1))•(c-3))

(((12•(b4))•(c-6))•——————————————————)•(2•5b(-5)c)

((3•5b3)•c4)

STEP

3

:

Equation at the end of step

3

:

(52b(-1)•c(-3))

(((12•(b4))•(c-6))•———————————————)•(2•5b(-5)c)

(3•5b3c4)

STEP

4

:

52b(-1)c(-3)

Simplify ————————————

(3•5b3c4)

Dividing exponential expressions :

4.1 b(-1) divided by b3 = b((-1) - 3) = b(-4) = 1/b4

Dividing exponential expressions :

4.2 c(-3) divided by c4 = c((-3) - 4) = c(-7) = 1/c7

Dividing exponents:

4.3 52 divided by 51 = 5(2 - 1) = 51 = 5

Equation at the end of step

4

:

5

(((12•(b4))•(c-6))•—————)•(2•5b(-5)c)

3b4c7

STEP

5

:

Equation at the end of step

5

:

5

(((22•3b4) • c(-6)) • —————) • (2•5b(-5)c)

3b4c7

STEP

6

:

Canceling Out :

6.1 Canceling out b4 as it appears on both sides of the fraction line

Dividing exponential expressions :

6.2 c(-6) divided by c7 = c((-6) - 7) = c(-13) = 1/c13

Canceling Out:

6.3 Canceling out 3 as it appears on both sides of the fraction line

Equation at the end of step

6

:

20

——— • (2•5b(-5)c)

c13

STEP

7

:

Multiplying exponents:

7.1 22 multiplied by 21 = 2(2 + 1) = 23

Multiplying exponents:

7.2 51 multiplied by 51 = 5(1 + 1) = 52

Dividing exponential expressions :

7.3 c1 divided by c13 = c(1 - 13) = c(-12) = 1/c12

Final result :

200

—————

b5c12 Answer:

Step-by-step explanation:

5 0

3 years ago

ИНННННННННННННННННННННННННННННННННННЕ МІНІМНІШНІШІЛІГІ

Gennadij [26K]

Answer: I don't believe i understand.

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

Which polynomials are in standard form?

Ksivusya [100]

b

b/c when it's rearranged large to small

4 0

2 years ago