Suppose $80 \%$ Of the Incoming Email Messages for a College's Computer System

Short Answer

Suppose $80 \%$ of the incoming email messages for a college's computer system are spam.
-After implementing a new spam blocker, if it turns out that a random sample of 200 messages contains $75 \%$ spam, would this constitute fairly convincing evidence that the (population) percentage of spam has been reduced from $80 \%$ ? Explain, based on your calculation in question "Use the CLT to approximate the probability that in a random sample of 200 incoming email messages at this college, the sample proportion of these messages that are spam would exceed .75.".