Let's attack this problem using the z-score concept. The sample std. dev. here is (0.25 oz)/sqrt(40), or 0.040. Thus, the z score representing 3.9 oz. is
3.9 - 4.0
z = -------------- = -2.5
0.040
In one way or another we must find the area under the std. normal curve that lies to the left of z = -2.5. Use a table of z-scores or a calculator with built-in statistics functions. According to my TI-83 Plus calculator, that area is
0.006. One way of interpreting this that with so small a standard deviation, most volumes of coffee put into the jars are very close to the mean, 4 oz.
The Circles Help Figure Out What Angle The Shape has
Solved in quadratic function
The answer :
X=(9,-1)
<h2>You need a reflection across the y-axis!</h2>
Answer:
0.9179 = 91.79% probability that a randomly selected call time will be less than 25 seconds
Step-by-step explanation:
Exponential distribution:
The exponential probability distribution, with mean m, is described by the following equation:

In which
is the decay parameter.
The probability that x is lower or equal to a is given by:

Which has the following solution:

The probability of finding a value higher than x is:

In this question:

Find the probability that a randomly selected call time will be less than 25 seconds?


0.9179 = 91.79% probability that a randomly selected call time will be less than 25 seconds