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3 years ago

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Seven customers enter a clothing store and are observed to determine if they will make a purchase. The store owner states that t

here is a 75% chance of a customer making a purchase. The random variable x represents a customer making a purchase. Calculate the mean, variance and standard deviation for the number of customers that make a purchase.

1 answer:

blondinia [14]3 years ago

3 0

Answer: Mean = 5.25

Variance = 1.3125

Standard deviation = 1.456

Step-by-step explanation:

The mean and variance of a binomial distribution with parameters n (number of trials) and p ( the probability of getting success in each trial) is given by :-

$\text{Mean}=np\\\\\text{Variance}=np(1-p)$

Given : The total number of enter a clothing store : n=7

The probability of a customer making a purchase= 0.75

Now,

$\text{Mean}=7(0.75)=5.25\\\\\text{Variance}=7(0.75)(0.25)=1.3125\\\\\Rightarrow\ \text{Standard deviation}=\sqrt{1.3125}=1.14564392374\approx1.1456$

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ANSWER

$y= -3{(x + 4)}^{2} + 2$

EXPLANATION

The given function is:

$y= -3x^2-24x-46$

Factor -3 for the first 2 terms.

$y= -3(x^2 + 8x)-46$

We add and subtract the square of the coefficient of x.

$y= -3(x^2 + 8x + {(4)}^{2} ) - - 3( {4)}^{2} -46$

Factor the perfect square trinomial.

$y= -3 {(x + 4)}^{2} ) + 48 -46$

The vertex form is:

$y= -3{(x + 4)}^{2} + 2$

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3 years ago

On a number line, what is the distance between -29 and 100? A) 29 B) 71 C) 81 D) 129

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So the distance between -29 and 100 is 129. The answer is D.

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2 years ago

Which is an equation of the line that is perpendicular to 3x+y=-5 and passes through the point (3, -7)?

nataly862011 [7]

Answer:

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Step-by-step explanation:

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Answer:

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Step-by-step explanation:

∠ 2 and 146° are corresponding angles and are congruent, then

∠ 2 = 146°

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2 years ago

Let R be the relation on the set of ordered pairs of positive integers such that ((a, b), (c, d)) ∈ R if and only if ad = bc. Ar

Veseljchak [2.6K]

Answer:

The given relation R is equivalence relation.

Step-by-step explanation:

Given that:

$((a, b), (c, d))\in R$

Where $R$ is the relation on the set of ordered pairs of positive integers.

To prove, a relation R to be equivalence relation we need to prove that the relation is reflexive, symmetric and transitive.

1. First of all, let us check reflexive property:

Reflexive property means:

$\forall a \in A \Rightarrow (a,a) \in R$

Here we need to prove:

$\forall (a, b) \in A \Rightarrow ((a,b), (a,b)) \in R$

As per the given relation:

$((a,b), (a,b) ) \Rightarrow ab =ab$ which is true.

$\therefore$ R is reflexive.

2. Now, let us check symmetric property:

Symmetric property means:

$\forall \{a,b\} \in A\ if\ (a,b) \in R \Rightarrow (b,a) \in R$

Here we need to prove:

$\forall {(a, b),(c,d)} \in A \ if\ ((a,b),(c,d)) \in R \Rightarrow ((c,d),(a,b)) \in R$

As per the given relation:

$((a,b),(c,d)) \in R$ means $ad = bc$

$((c,d),(a,b)) \in R$ means $cb = da\ or\ ad =bc$

Hence true.

$\therefore$ R is symmetric.

3. R to be transitive, we need to prove:

$if ((a,b),(c,d)),((c,d),(e,f)) \in R \Rightarrow ((a,b),(e,f)) \in R$

$((a,b),(c,d)) \in R$ means $ad = cb$ .... (1)

$((c,d), (e,f)) \in R$ means $fc = ed$ ...... (2)

To prove:

To be $((a,b), (e,f)) \in R$ we need to prove: $fa = be$

Multiply (1) with (2):

$adcf = bcde\\\Rightarrow fa = be$

So, R is transitive as well.

Hence proved that R is an equivalence relation.

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