Suppose that you randomly draw one card from a standard deck of 52 cards. after writing down which card was drawn, you replace the card, and draw another card. you repeat this process until you have drawn 19 cards in all. what is the probability of drawing at least 8 clubs? for the experiment above, let x denote the number of clubs that are drawn. for this random variable, find its expected value and standard deviation.

The probability is 0.0775

The expected value is 4.75 clubs

The standard deviation is 1.8875 clubs

Step-by-step explanation:

The variable X follows a binomial distribution, because we have n identical and independent events (19 cards) with a probability p of success and 1-p of fail (there is a probability of 1/4 to be club and 3/4 to be diamond, heart or spade). Then, the probability that x of the n cards are club is:

So, the probability P of drawing at least 8 clubs is:

P = P(8) + P(9) + P(10) + ... + P(18) + P(19)

Replacing, the values of x, from 8 to 19, on the equation above, we get:

P = 0.0775

Additionally, the expected value E(x) and standard deviationS(x) for this distribution is given by:

E(x)=np = 19(0.25) = 4.75

step-by-step explanation:

12475909

answer:

payment just for service  

→

$

87.12

payment for service including tax

→

$

94.09

explanation:

service only with 20% tip  

→

$

72.6

(

1

+

20

100

)

=

$

87.12

in the opening of the question the word 'service' is associated only with the pretax value.

the closing part of the question asks: how much did she pay for the  

service

−−−−−−  

so technically the answer is  

→

$

72.6

(

1

+

20

100

)

=

$

87.12

however, the intention of the question provider may have been that your answer is to be  

$

87.12

(

1

+

8

100

)

=

$

94.09

to 2 decimal places.

'

payment just for service  

→

$

87.12

payment for service including tax

→

$

94.09

tony b

mar 21, 2017

answer:

trying to explain it another way

explanation:

service charge  

.

→

$

72.60

20% tip  

20

100

×

$

72.60

=

$

14.52

−−−−−−  

←

add

$

87.12

tax  

8

100

×

$

87.12

=

$

6.97

−−−−−  

←

add

$

94.09

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