if there is a 12 percent chance to get something and you need to get 90 of those things how many tries would it take?

The time taken to assemble a laptop computer in a certain plant is a random variable having a normal distribution of 20 hours an

ludmilkaskok [199]

Answer:

a) 40.13% probability that a laptop computer can be assembled at this plant in a period of time of less than 19.5 hours.

b) 34.13% probability that a laptop computer can be assembled at this plant in a period of time between 20 hours and 22 hours.

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this question:

$\mu = 20, \sigma = 2$

a)Less than 19.5 hours?

This is the pvalue of Z when X = 19.5. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{19.5 - 20}{2}$

$Z = -0.25$

$Z = -0.25$ has a pvalue of 0.4013.

40.13% probability that a laptop computer can be assembled at this plant in a period of time of less than 19.5 hours.

b)Between 20 hours and 22 hours?

This is the pvalue of Z when X = 22 subtracted by the pvalue of Z when X = 20. So

X = 22

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{22 - 20}{2}$

$Z = 1$

$Z = 1$ has a pvalue of 0.8413

X = 20

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{20 - 20}{2}$

$Z = 0$

$Z = 0$ has a pvalue of 0.5

0.8413 - 0.5 = 0.3413

34.13% probability that a laptop computer can be assembled at this plant in a period of time between 20 hours and 22 hours.

4 0

3 years ago

In a clinical study, volunteers are tested for a gene that has been found to increase the risk for a disease. The probability th

MrRa [10]

Answer:

a) 0.984

b) 20 people

Step-by-step explanation:

a)

If The probability that a person carries the gene is 0.1, then in a sample of 20 people, 2 should carry the gene.

Now, we want to know how many samples there are with this property.

Since we have 20 elements where 18 are alike (do not carry the gene) and 2 are alike (carry the gene), we have to compute the number of permutations of 20 elements in which 18 are alike and 2 are alike. This number is

$\frac{20!}{18!2!}=190$

In this 190 20-tuples there are only 3 where the 2 carriers of the gene are in the first 3 places, namely

(1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)

(1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)

(0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)

where 1=carries the gene, 0=does not carry the gene.

So there are 190-3 = 187 elements in which the first 3 elements have no 2 carriers, hence the probability that 4 or more people will have to be tested until 2 of them with the gene are detected is 187/190 = 0.984 (98.4%) rounded to three decimal places.

b)

Given that the probability that a person carries the gene is 0.1, then in a sample of 20 people, 20*0.1 = 2 should carry the gene.

4 0

3 years ago

Chris took a vacation trip to maine, where sales tax on taxable items is 5%. in maine, prepared food and lodging are taxed an ad

12345 [234]

So, it's just an annoying problem. Keep the tax rates in mind for each thing.
$70 of souvenirs mean the tax is 5% since it is not prepared food, lodging, or auto rentals.
$580 on prepared food means that has 7% tax because it is special.
$620 on the car has a 10% tax, as stated in the problem.
So do 70(1.05)+580(1.07)+620(1.1) to get $1376.1.0

6 0

2 years ago

Read 2 more answers

a plumber charges an initial fee of $200 plus an hourly fee of $50. Mr.Collins paid the plumber $450. How many hours did the plu

Advocard [28]

The plumber worked for 5 hours because 450-200=250 which gets rid of the initial fee so 250 divided by 50 is 5

8 0

3 years ago

The coefficient of 8 • 2N is _____.

lesantik [10]

Answer:

16 is the coefficient of N.

Step-by-step explanation:

Coefficient is a multiplicative factor in some term of a polynomial, a series, or any expression; it is usually a number, but may be any expression. In the latter case, the variables appearing in the coefficients are often called parameters, and must be clearly distinguished from the other variables. The coefficients of an algebraic term can be positive or negative, and this multiplies the unknown term.

For example:

In 2a, 2 is the coefficient of a;

In x, 1 is the coefficient of x but it is not visible;

In 2/3p, 2/3 is the coefficient of p;

In -3f, -3 is the coefficient of f;

In 3 × 6t, 18 is the coefficient of t.

Variable is a symbol, commonly a single letter, that represents a number, called the value of the variable, which is either arbitrary, not fully specified, or unknown. Making algebraic computations with variables as if they were explicit numbers allows one to solve a range of problems in a single computation. A typical example is the quadratic formula, which allows one to solve every quadratic equation by simply substituting the numeric values of the coefficients of the given equation for the variables that represent them.

So,

In 8 × 2N, 16 is the coefficient of N ( 8 × 2 = 16)

N is the variable.

7 0

3 years ago

if there is a 12 percent chance to get something and you need to get 90 of those things how many tries would it take?​

if there is a 12 percent chance to get something and you need to get 90 of those things how many tries would it take?