How many even numbers can be formed from the digits 1,2,3,4,5?

5^n=0.2 need to find value of n

lozanna [386]

Answer:

Below

Step-by-step explanation:

5^n = 0.2

First write the number in exponential form with the base of 5 :

5^n = 5^-1

Because the bases are the same, we can set the exponents as equal :

x = -1

Hope this helps! Best of luck <3

6 0

3 years ago

Helpppppppppppppppppppppppppp

avanturin [10]

Answer:

1/125, 1/625, 1/3125

Step-by-step explanation:

a8=25*(1/5)^7=25/78125=1/3125

5 0

3 years ago

When circuit boards used in the manufacture of compact disc players are tested, the long-run percentage of defectives is 5%. Let

sergiy2304 [10]

Answer:

(a) P(X=3) = 0.093

(b) P(X≤3) = 0.966

(c) P(X≥4) = 0.034

(d) P(1≤X≤3) = 0.688

(e) The probability that none of the 25 boards is defective is 0.277.

(f) The expected value and standard deviation of X is 1.25 and 1.089 respectively.

Step-by-step explanation:

We are given that when circuit boards used in the manufacture of compact disc players are tested, the long-run percentage of defectives is 5%.

Let X = the number of defective boards in a random sample of size, n = 25

So, X ∼ Bin(25,0.05)

The probability distribution for the binomial distribution is given by;

$P(X=r)= \binom{n}{r} \times p^{r}\times (1-p)^{n-r} ; x = 0,1,2,......$

where, n = number of trials (samples) taken = 25

r = number of success

p = probability of success which in our question is percentage

of defectivs, i.e. 5%

(a) P(X = 3) = $\binom{25}{3} \times 0.05^{3}\times (1-0.05)^{25-3}$

= $2300 \times 0.05^{3}\times 0.95^{22}$

= 0.093

(b) P(X $\leq$ 3) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3)

= $\binom{25}{0} \times 0.05^{0}\times (1-0.05)^{25-0}+\binom{25}{1} \times 0.05^{1}\times (1-0.05)^{25-1}+\binom{25}{2} \times 0.05^{2}\times (1-0.05)^{25-2}+\binom{25}{3} \times 0.05^{3}\times (1-0.05)^{25-3}$

= $1 \times 1 \times 0.95^{25}+25 \times 0.05^{1}\times 0.95^{24}+300 \times 0.05^{2}\times 0.95^{23}+2300 \times 0.05^{3}\times 0.95^{22}$

= 0.966

(c) P(X $\geq$ 4) = 1 - P(X < 4) = 1 - P(X $\leq$ 3)

= 1 - 0.966

= 0.034

(d) P(1 ≤ X ≤ 3) = P(X = 1) + P(X = 2) + P(X = 3)

= $\binom{25}{1} \times 0.05^{1}\times (1-0.05)^{25-1}+\binom{25}{2} \times 0.05^{2}\times (1-0.05)^{25-2}+\binom{25}{3} \times 0.05^{3}\times (1-0.05)^{25-3}$

= $25 \times 0.05^{1}\times 0.95^{24}+300 \times 0.05^{2}\times 0.95^{23}+2300 \times 0.05^{3}\times 0.95^{22}$

= 0.688

(e) The probability that none of the 25 boards is defective is given by = P(X = 0)

P(X = 0) = $\binom{25}{0} \times 0.05^{0}\times (1-0.05)^{25-0}$

= $1 \times 1\times 0.95^{25}$

= 0.277

(f) The expected value of X is given by;

E(X) = $n \times p$

= $25 \times 0.05$ = 1.25

The standard deviation of X is given by;

S.D.(X) = $\sqrt{n \times p \times (1-p)}$

= $\sqrt{25 \times 0.05 \times (1-0.05)}$

= 1.089

8 0

3 years ago

A random sample of n people selected from a large population will be asked whether they have read a novel in the past year. Let

kozerog [31]

Answer:

b. A binomial variable with 25 independent trials

Step-by-step explanation:

The conducted experiment is binomial experiment because outcome can be divided into success or failure. The success would be the people who read novel in the past year and also responses are independent of each other. We have to find the number of trials n in the given problem.

we are given that variance of R=6 and p=probability of success=0.4.

We know that variance of binomial distribution is

Variance=npq

where q=1-p=1-0.4=0.6.

By putting the values in variance formula, we can get the value of n.

6=n*0.4*0.6

6=0.24*n

n=6/0.24

n=25

Hence, random variable R is a binomial variable with 25 independent trials.

4 0

3 years ago

PLZZZZZZZZZ NEED HELP ASAP QUESTION WORTH 20 POINTS

andrezito [222]

Part A: After 9 days the radius of algae was approximately 12.81 mm. The reasonable domain to point is (0,9).

Part B: The 9 on the y-intercept represents the amount of algae the experiment started with.

Part C: (12.81-10.12)/7=0.38

5 0

3 years ago