Concerned about airport and airline security, the Federal Aviation Administratio
ID: 3270249 • Letter: C
Question
Concerned about airport and airline security, the Federal Aviation Administration (FAA) has begun imposing sanctions against airlines that fail security tests. Once series of tests conducted at Los Angles International Airport (LAX) showed that security guards detected only 73 of the 100 mock weapons carried on by FAA inspectors or included in their carryon luggage. According to the FAA, "this detection rate was well below the national rate of 80." is there sufficient evidence to conclude that the mock weapon detection rate at LAX is less than the national rate of 0.80 degree i.e., is LAX lax? Test at a 5% significance level using appropriate hypothesis testing procedures. Also determine and interpret the p-value.Explanation / Answer
Here we want to test that "Is the there sufficient evidence to conclude that the mock weapon detection rate at LAX is less than the national average rate of 0.80"?
So null hypothesis is H0 : P = 0.73
and alternative hypothesis is H1 : P < 0.80
We can used one sample proportion z test.
Let' write given information.
n = sample size = 100
x = number of favourable events = 73
level of significance = 0.05
Using minitab.
The command for one sample proportion z test in minitab is
Stat>>>Basic statistics>>>1-proportion...
Then click on summarized data
number of events = x = 73
Number of trials = n = 100
Click on "Perform hypothesis test
Hypothesized proportion = P = 0.5 (because under the null hypothesis P = 0.5)
then click on option
Level of confidence in percentage = c = ( 1- lpha)*100 = = (1 -0.05)*100 = 95.0
so put "Confidence level " = 95.0
Alternative = less than
then click on "Use test and interval based on normal approximation"
Then click on OK and again click on OK
So we get the following output
MTB > POne 100 73;
SUBC> Test 0.8;
SUBC> Alternative -1.
Test and CI for One Proportion
Test of p = 0.8 vs p < 0.8
95% Upper Exact
Sample X N Sample p Bound P-Value
1 73 100 0.730000 0.802075 0.056
Decision rule:
1) If p-value < level of significance (alpha) then we reject null hypothesis
2) If p-value > level of significance (alpha) then we fail to reject null hypothesis.
Here p value = 0.056 > 0.05 so we used 2nd rule.
That is we failed to reject null hypothesis
Conclusion:
At 5% level of significance there are not sufficient evidence to say that the mock weapon detection rate at LAX is less than the national average rate of 0.80.
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