$6\mathrm{.}84$ Information $6\mathrm{.}7$ Exercise Set $2$

information security comrity Buzz provides news for the

September $24,2016,$ it

international survey of Interned that based on a large

have installed security solutions

${?}_{15}$ se to access the Internet $($www on all of the devices they

particles$/21-29-60-$kaspersky$-$lab$-$informationsecuritybuzz.com

index$/,$ retrieved May $2,2017).$

a$.$ Suppose that the true proportion of Internet users who

have security solutions on all of the devices they use

to access the Internet is $0\mathrm{.}60.$ If $20$ Internet users are

selected at random, what is the probability that more than

$10$ have security solutions installed on all devices used to

access the Internet?

b$.$ Suppose that a random sample of Internet users is select$-$

ed$.$ Which is more likely $-$ that more than $15$ have secu$-$

rity solutions on all devices used to access the Internet or

that fewer than $5$ have security solutions on all devices

used to access the Internet? Justify your answer based on

probability calculations.