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

yes

step-by-step explanation:

so of course you want to start by plugging the 5 in which goes to 7(5)+3(5)=50 because 7*5=35 and 3*5=15 and then add them together, then plug in the 5 to the other equation as well 9(5)+5=50 because 9*5= 45 and then add 5 and so yes they are equivalent.