Question

Refer to the sample data for polygraph tests shown below. If one of the test subjects is randomly​ selected, what is the probability that the subject is not​ lying? Is the result close to the probability of

0.449

for a negative test​ result?

   No (Did Not Lie)   Yes (Lied)
Positive test results   14   40
Negative test results   33   11

The probability that a randomly selected polygraph test subject was not lying is

nothing.

​(Type an integer or decimal rounded to three decimal places as​ needed.)

Is the result close to the​ probability, rounded to three decimal​ places, of

0.449

for a negative test​ result?

▼

No,

Yes,

because there is

▼

more than

less than

exactly

a 0.050 absolute difference between the probability of a true response and the probability of a negative test result.

Answer 1

Solution:

No (Did Not Lie)   Yes (Lied) total
Positive test results   14   40 54
Negative test results   33   11 44

total 47 51 98

L as the randomly selected polygraph test subject was not lying, the event N as the randomly selected test is negative test.

The total number of possible ways is 98

N(S) =98

number of possible ways that a randomly selected polygraph test subject was not lying is = 14 +33 = 47

The required probability is, N(L) / N(S) = 47/98 = 0.479

The number of possible ways that a randomly selected test is negative test is,

N(N)= 33 + 11 =44

The required probability

P(N) = 44/98 =0.4489

Yes, because there is less than a 0.050 absolute difference between the probability of a true response and the probability of a negative test result.