Answer:
The correct option is (a).
Explanation:
The correlation coefficient is a statistical degree that computes the strength of the linear relationship amid the relative movements of the two variables (i.e. dependent and independent).It ranges from -1 to +1.
In this case, a hypothesis test for a significant positive correlation is to be performed to determine whether the claim made by the policeman is true or not.
The hypothesis can be defined as follows:
H₀: There isn't a positive correlation between the number of text messages drivers send while driving and the likelihood of being in a car accident, i.e. ρ ≤ 0.
Hₐ: There is a positive correlation between the number of text messages drivers send while driving and the likelihood of being in a car accident, i.e. ρ > 0.
Consider the first option.
The sample correlation computed from 30 samples data is,
r = 0.38
The correlation is positive and the sample size is large enough to rely on the sample data.
The p-value of the test is, p < 0.05.
As the p-value is less than 5% level of significance, the null hypothesis will be rejected.
Thus, concluding that there enough evidence to support the policeman's belief.
Thus, the correct option is (a).