assume that when adults with smartphones are randomly selected 42 use them in meetings or classes if 15 adult smartphones are randomly selected, find the probability that "fewer" than 4 of them use their smartphones

Complete Question

Assume that when adults with smartphones are randomly selected 42% use them in meetings or classes if 15 adult smartphones are randomly selected, find the probability that "fewer" than 4 of them use their smartphones

The  probability is  

Step-by-step explanation:

From the question we are told that

      The proportion of those that use smartphone in meeting and classes is  p = 0.42

     The sample size is  

   The proportion of those that don't use  smartphone in meeting and classes is  

=>        

=>        

Now  from the question we can deduce that the usage of the smartphone is having a  binomial  distribution since there is only two outcome  

So  the probability that "fewer" than 4 of them use their smartphones is mathematically evaluated as

       =

=>    

Where   implies 15  combination 0 which has a value of  1 this is obtained using a scientific calculator

  So for the rest of the equation we will be making use of a scientific calculator to obtain the combinations

substituting values

=>      

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step-by-step explanation: