A researcher reported that 71.8% of all email sent in a recent month was spam. A system manager at a large corporation believes that the percentage at his company may be 78%. He examines a random sample of 500 emails received at an email server, and finds that 367 of the messages are spam. Can you conclude that the percentage of emails that are spam differs from 78%? Use both α=0.05 and α=0.10 levels of significance and the P-value method with the TI-84 Plus calculator.
a. state null and alternative hypothesis. what tail is the hypothesis test?
b. Compute the value of the test statistic.
c. Using α=0.05, can you conclude that greater than 71% of emails are spam?
d. Using α=0.10, can you conclude that greater than 71% of emails are spam?
e. state conclusion