1/6 +3/8 = in simplest form

A manufacturer of Christmas light bulbs knows that 10% of these bulbs are defective. It is known that light bulbs are defective

andriy [413]

Answer:

(a) P(X $\leq$ 20) = 0.9319

(b) Expected number of defective light bulbs = 15

(c) Standard deviation of defective light bulbs = 3.67

Step-by-step explanation:

We are given that a manufacturer of Christmas light bulbs knows that 10% of these bulbs are defective. It is known that light bulbs are defective independently. A box of 150 bulbs is selected at random.

Firstly, the above situation can be represented through binomial distribution, i.e.;

$P(X=r) = \binom{n}{r} p^{r} (1-p)^{2} ;x=0,1,2,3,....$

where, n = number of samples taken = 150

r = number of success

p = probability of success which in our question is % of bulbs that

are defective, i.e. 10%

Now, we can't calculate the required probability using binomial distribution because here n is very large(n > 30), so we will convert this distribution into normal distribution using continuity correction.

So, Let X = No. of defective bulbs in a box

Mean of X, $\mu$ = $n \times p$ = $150 \times 0.10$ = 15

Standard deviation of X, $\sigma$ = $\sqrt{np(1-p)}$ = $\sqrt{150 \times 0.10 \times (1-0.10)}$ = 3.7

So, X ~ N( $\mu = 15, \sigma^{2} = 3.7^{2})$

Now, the z score probability distribution is given by;

Z = $\frac{X-\mu}{\sigma}$ ~ N(0,1)

(a) Probability that this box will contain at most 20 defective light bulbs is given by = P(X $\leq$ 20) = P(X < 20.5) ---- using continuity correction

P(X < 20.5) = P( $\frac{X-\mu}{\sigma}$ < $\frac{20.5-15}{3.7}$ ) = P(Z < 1.49) = 0.9319

(b) Expected number of defective light bulbs found in such boxes, on average is given by = E(X) = $n \times p$ = $150 \times 0.10$ = 15.

Standard deviation of defective light bulbs is given by = S.D. = $\sqrt{np(1-p)}$ = $\sqrt{150 \times 0.10 \times (1-0.10)}$ = 3.67

8 0

3 years ago

Plz someone answer this with an explanation

worty [1.4K]

Answer:

1/3

Step-by-step explanation:

8 0

3 years ago

Identify which property you would use first to solve the following equation.

IceJOKER [234]

Answer:

Distributive property

Step-by-step explanation:

In order to solve this equation we first need to distribute 3 into 2y+5, we use the distributive property to do this.

5 0

2 years ago

Pls answer i’ll give brainliest

oee [108]

Answer:

PQR and JK

Step-by-step explanation:

ΔGHJ ≈ ΔPQR by the Transitive Property of Congruence. GH ≈ JK since corresponding parts of congruent figures are congruent.

Pls mark as brainliest. I would really appreciate it if you did.

4 0

3 years ago

Emmy throws a doggy toy up in the air. The path of the toy is modeled by the function f(x)=−x^2+4x+5, where x is the number of f

Molodets [167]

Answer:

9feet

Step-by-step explanation:

Given the path of the toy modeled by the function f(x)=−x^2+4x+5, where x is the number of feet the toy is from Emmy and f(x) is the height of the toy.

AT maximum height, the velocity of the toy will be zero. Hence;

df(x)/dx = 0

-2x + 4 = 0

-2x = -4

x = -4/-2

x = 2

Get the maximum height;

Substitute x = 2 into the given function;

f(x)=−x^2+4x+5

f(2)=−2^2+4(2)+5

f(2) = -4+8+5

f(2) = 9feet

Hence the maximum height of the toy is 9feet

4 0

3 years ago