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3 years ago

15

To play at bingo night there’s a $10 cover charge +2 dollar per bingo card. Write an equation for the cost (y) based on the numb

er on bingo cards (x)

1 answer:

jasenka [17]3 years ago

4 0

Answer:

y = 2x+10

Step-by-step explanation:

y is the cost (which we don't know)

2x is the $2 per card with x representing the number of cards (which we don't know)

And of course 10 is the cover charge.

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Isla flipped a coin 30 times. The coin landed heads up 9 times and tails up 21 times.

Debora [2.8K]

Answer:

both are equal

Step-by-step explanation:

there are two side tails and heads so there a 1/2 chance it will land on heads

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3 years ago

(-8)^-2 / 3^-4 simplify the expression. Write your answer using only positiv exponents.

spin [16.1K]

Answer:

3^4 / 8^2 or 81/64

Step-by-step explanation:

(-8)^-2 / 3^-4 =

= 3^4 / (-8)^2

= 3^4 / 8^2

= 81/64

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3 years ago

Find the mean, variance &a standard deviation of the binomial distribution with the given values of n and p.

MrMuchimi

A random variable following a binomial distribution over $n$ trials with success probability $p$ has PMF

$f_X(x)=\dbinom nxp^x(1-p)^{n-x}$

Because it's a proper probability distribution, you know that the sum of all the probabilities over the distribution's support must be 1, i.e.

$\displaystyle\sum_xf_X(x)=\sum_{x=0}^n\binom nxp^x(1-p)^{n-x}=1$

The mean is given by the expected value of the distribution,

$\mathbb E(X)=\displaystyle\sum_xf_X(x)=\sum_{x=0}^nx\binom nxp^x(1-p)^{n-x}$
$\mathbb E(X)=\displaystyle\sum_{x=1}^nx\frac{n!}{x!(n-x)!}p^x(1-p)^{n-x}$
$\mathbb E(X)=\displaystyle\sum_{x=1}^n\frac{n!}{(x-1)!(n-x)!}p^x(1-p)^{n-x}$
$\mathbb E(X)=\displaystyle np\sum_{x=1}^n\frac{(n-1)!}{(x-1)!((n-1)-(x-1))!}p^{x-1}(1-p)^{(n-1)-(x-1)}$
$\mathbb E(X)=\displaystyle np\sum_{x=0}^n\frac{(n-1)!}{x!((n-1)-x)!}p^x(1-p)^{(n-1)-x}$
$\mathbb E(X)=\displaystyle np\sum_{x=0}^n\binom{n-1}xp^x(1-p)^{(n-1)-x}$
$\mathbb E(X)=\displaystyle np\sum_{x=0}^{n-1}\binom{n-1}xp^x(1-p)^{(n-1)-x}$

The remaining sum has a summand which is the PMF of yet another binomial distribution with $n-1$ trials and the same success probability, so the sum is 1 and you're left with

$\mathbb E(x)=np=126\times0.27=34.02$

You can similarly derive the variance by computing $\mathbb V(X)=\mathbb E(X^2)-\mathbb E(X)^2$ , but I'll leave that as an exercise for you. You would find that $\mathbb V(X)=np(1-p)$ , so the variance here would be

$\mathbb V(X)=125\times0.27\times0.73=24.8346$

The standard deviation is just the square root of the variance, which is

$\sqrt{\mathbb V(X)}=\sqrt{24.3846}\approx4.9834$

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3 years ago

Which equation would you use to find the distance between the two points?

navik [9.2K]

The answer is because of the distance between the two please make me the Brainliest!! :)))

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2 years ago

X -1 < -4<br><br> What is ittttttttt

Kamila [148]

Answer:

x<-3

Step-by-step explanation:

x-1+1<-4+1

x<-3

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3 years ago