Answer:
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
- X is the sample mean (18 hours)
- M is the average hours dentists spend per week on fillings (20 hours)
- s is the standard deviation (10 hours)
- N is the sample size (144)
Putting the numbers, we get:
z(18)=![\frac{18-20}{\frac{10}{\sqrt{144} } }=-2.4](https://tex.z-dn.net/?f=%5Cfrac%7B18-20%7D%7B%5Cfrac%7B10%7D%7B%5Csqrt%7B144%7D%20%7D%20%7D%3D-2.4)
Using z- table we can find that P(z<z(18)) = 0.0082
-18
1) Distribute the -6 to the parentheses
-4 - (6*7) - (-6*3)
2) Simplify
-4 - 42 + 18
-18
Answer:
$212.40
Step-by-step explanation:
180+ (180* 18%)= Total Cost
180+ 32.40= Total Cost
212.40= Total Cost
It is prime, it has no factors besides 1,23