SOLUTION: A telephone company claims that less than 20% of all college students use prepaid phone cards. A random sample of 250 students revealed that 41 of them used prepaid phone cards.
Algebra ->
Probability-and-statistics
-> SOLUTION: A telephone company claims that less than 20% of all college students use prepaid phone cards. A random sample of 250 students revealed that 41 of them used prepaid phone cards.
Log On
Question 438588: A telephone company claims that less than 20% of all college students use prepaid phone cards. A random sample of 250 students revealed that 41 of them used prepaid phone cards. Test the company's claim at the 0.05 level of significance. Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! A telephone company claims that less than 20% of all college students use prepaid phone cards. A random sample of 250 students revealed that 41 of them used prepaid phone cards. Test the company's claim at the 0.05 level of significance.
--------------------------------------
Ho: p >= 0.20
Ha: p < 0.20 (claim)
-----------------------
P-hat = 41/250 = 0.164
----
test stat: z(0.164) = (0.164-0.20)/sqrt(0.2*0.8/250) = -1.4230
-----
p-value = P(z < -1.4230) = 0.7737
----
Since the p-value is greater than 5%, fail to reject Ho.
----
The test supports the claim.
==================================
Cheers,
Stan H.
==========================
(