Answer:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".
Solution to the problem
For this case we select a sample of n =100
From the central limit theorem we know that the distribution for the sample mean is given by:
So then the sample mean would be:
And the standard deviation would be:
Answer:
<h2>-1/5</h2>
Step-by-step explanation:
Starting at -3/5 you need to subtract -2/5.
When you subtract a negative number, the sign flips and you add instead. Often, you are taught that two similar signs means add and two opposite signs mean minus.
<em>+ + = +</em>
<em>- - = -</em>
<em>+ - = -</em>
<em>- + = -</em>
<em />
This means -3/5 - -2/5 becomes -3/5 + 2/5.
Because you are adding, you move two lines to the right on the number line.
You end at -1/5.
Answer: 4 hours
Step-by-step explanation:
Let the number of hours that the repair take be represented by h.
Since the cost of Sam's car repair is $20 an hour plus $180 for parts and the total cost was $260, this can be formed into an equation as:
180 + 20h = 260.
20h = 260 - 180.
20h = 80
h = 80 / 20
h = 4
The repair took 4 hours
1.TR is the two equations combined so 18x+26