The speed limit on a road is 45 mph. you want to clock the speed of a random sample of cars to test the hypothesis that the average speed of cars is greater than the speed limit. what kind of test would you use?

a left tailed test
a right tailed test
a two tailed test

the answer is a right tailed but i don't know why someone explain

A right tailed test

Step-by-step explanation:

In hypothesis testing there are two types of hypotheses;

The null hypothesis, H0 and the alternative hypothesis, Ha. The null hypothesis is the hypothesis of no difference and as such it always has an equality sign;

=, ≤, ≥

On the other hand the alternative hypothesis complements the null hypothesis meaning that if the null hypothesis is rejected then we take the alternative hypothesis to be true.

The kind of test to be carried out in hypothesis testing emanates from the inequality sign of the alternative hypothesis. The following are the key points to note, if the alternative hypothesis contains;

≠, then this automatically becomes a two tailed test

<, then this automatically becomes a left tailed test since the inequality sign is pointing towards the left.

>, then this automatically becomes a right tailed test since the inequality sign is pointing towards the right.

In the scenario given the following will be the set of hypotheses to be tested;

H0: u ≤ 45

Ha: u > 45 ( the hypothesis that the average speed of cars is greater than the speed limit)

The kind of test to be used is thus a right tailed test since the alternative hypothesis contains >.

I hope this will help.