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| Question 1209507:  Recall that there are 4 suits - spades, hearts, clubs, and diamonds - in a standard deck of playing cards. Suppose you play a game in which you draw a card, record the suit, replace it, shuffle, and repeat until you have observed 10 cards. Define X = numbers of spades observed.
 
 Find the probability of observing 3 or fewer spades in this game. Round to three decimal places.
 
 Found 3 solutions by  mccravyedwin, ikleyn, math_tutor2020:
 Answer by mccravyedwin(409)
      (Show Source): 
You can put this solution on YOUR website! 
Probability of getting a spade = 1/4
That's a cumulative binomial distribution problem
Got a TI-84?
2nd, vars, scroll to binomcdf enter 
trials:10
p:1/4
x value:3
Paste
Scroll to Paste
enter
see binomcdf(10,1/4,3)
enter
0.7758750914 round to 0.776
EdwinAnswer by ikleyn(52879)
      (Show Source): 
You can put this solution on YOUR website! . Recall that there are 4 suits - spades, hearts, clubs, and diamonds - in a standard deck
 of playing cards. Suppose you play a game in which you draw a card, record the suit,
 replace it, shuffle, and repeat until you have observed 10 cards. Define X = numbers of spades observed.
 Find the probability of observing 3 or fewer spades in this game. Round to three decimal places.
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 
In this game, there are 4 suits, and every suit has the same number of card, 13,
so the total number of cards in a standard deck is 4*13 = 52.
At each step, this game returns us to the same initial condition, due to replacing and 
shuffling the cards.
Therefore, this game is a typical binomial experiment.  At each trial, we have a spade 
with the probability 1/4 = 0.25  or any other suit card with the probability 3/4 = 0.75.
So, they want you calculate the probability of having success (having a spade) 3 or fever 
times of 10 trials.
Use the standard formula for the binomial probability
    P(X <= 3) = P(0) + P(1) + P(2) + P(3)
where  P(k) =  ,  are binomial coefficients  =  .
Now calculate using a calculator
     P(0) =  =  = 0.056313515;
     P(1) =  =  = 0.187711716;
     P(2) =  =  = 0.281567574;
     P(3) =  =  = 0.250282288.
Finally, add the number and get 
    P(X <= 3) = 0.056313515 + 0.187711716 + 0.281567574 + 0.250282288 = 0.775875092.
Round it to 3 decimals.  So,  P(X <= 3) = 0.776  (rounded).    ANSWER
You may check this result by using a convenient online binomial calculator at
https://stattrek.com/online-calculator/binomial.aspxAt this point, the problem is solved completely.
 
 
 
Answer by math_tutor2020(3817)
      (Show Source): 
You can put this solution on YOUR website! If your teacher lets you use a spreadsheet, then you can quickly find the answer using the BinomDist function.
 
 The template is
 =BinomDist(x,n,p,c)
 x = number of successes
 n = number of trials
 p = probability of success
 c = cumulative flag
 
 In this case x = 3, n = 10, p = 1/4 = 0.25
 c = 1 indicates that we're adding binomial probability values from x = 0 to x = 3
 
 Therefore the full command to type in would be:
 =BinomDist(3,10,0.25,1)
 This leads to this approximate value 0.775875
 which rounds to the final answer 0.776
 
 Side note: Don't forget the equal sign up front of the BinomDist command.
 
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