The pew internet and american life project reported wednesday, april 18th that two- thirds (67%) of young adults with profiles on social-networking sites have restricted access to their profiles by requiring passwords or making them available only to friends on an approved list ("study: teens protecting their profiles" posted: 10: 54 a. m. edt, april 19, 2007 on cnn. com). a researcher believes that military personnel are more careful with keeping themselves safe online and surveys a random sample of 100 enlisted military personnel students and finds that 78 students restrict access to their profiles. does this indicate at the 5% significance level that a larger proportion of military personnel protect their profiles on social-networking sites?

At 5% significance level, larger proportion of military personnel students protect their profiles on social-networking sites than young adults with profiles on social-networking sites.

Step-by-step explanation:

let p be the proportion of military personnel students who restrict access to their profiles. Then null and alternative hypotheses are:

: p=0.67 (67%)

: p>0.67

We need to calculate z-statistic of sample proportion:

z= where

Then z= ≈ 2.34

The corresponding p-value is 0.0096. Since 0.0096<0.05 (significance level) we can reject the null hypothesis and conclude at 5% significance level that larger proportion of military personnel students protect their profiles on social-networking sites than young adults with profiles on social-networking sites.

this is the formula: v = the value of investment at the end of the time period

p = the principal amount (the initial amount invested)

r = the annual interest rate

n = the annual frequency of compounding (how many times a year interest is added)

t = the number of years the money is invested

^ means raise to the power of