# (Refer to Exercise 15.6) A recent I survey states that 48% of mobile devices are iPhones. In order to learn more lout how the iPhone works, a student starts asking his friends if they use an I'liunc. Let X be the number of friends he will need to ask until he finds one 10 uses an iPhone.a. What is the

(Refer to Exercise 15.6) A recent I survey states that 48% of mobile devices are iPhones. In order to learn more lout how the iPhone works, a student starts asking his friends if they use an I'liunc. Let X be the number of friends he will need to ask until he finds one 10 uses an iPhone.

a. What is the expected value of X?

b. What is the standard deviation of X?

c. Show the labeled graph of the mass for this story.

d. Show the labeled graph of the CDF for this story.

a. What is the expected value of X?

b. What is the standard deviation of X?

c. Show the labeled graph of the mass for this story.

d. Show the labeled graph of the CDF for this story.

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**Related Book For**

## Introduction to Probability

1st edition

Authors: Mark Daniel Ward, Ellen Gundlach

ISBN: 978-0716771098