Anational dental association conducted a survey to find the average (mean) amount of time dentists spend on dental fillings per week. based on a simple random sample, they surveyed 144 dentists. the statistics showed that dentists spent an average of 20 hours per week on fillings with a standard deviation of 10 hours. what is the probability of finding a sample mean less than 18 hours?

The probability of finding a sample mean less than 18 hours is 0.0082

Step-by-step explanation:

To find the probability of finding a sample mean less than 18 hours, we need to calculate the z-score of this sample mean 18. And the probability of finding a sample mean less than 18 hours is P(z<z(18)).

Z-score can be calculated as follows:

z(18)= where

Putting the numbers, we get:

z(18)=

Using z- table we can find that P(z<z(18)) = 0.0082

step-by-step explanation:

at each of the parallel lines adjacent angles are supplementary. the angles have special names identifying their positions with respect to the parallel lines and transversal. they are corresponding angles, alternate interior angles, or alternate exterior angles. an angles is congruent to its matched angle.