The value of the z statistic for the considered data is given by: Option A: -3.87 approximately.
<h3>How to find the z score (z statistic) for the sample mean?</h3>
If we're given that:
- Sample mean =
- Sample size = n
- Population mean =
- Sample standard deviation = s
Then, we get:
If the sample standard deviation is not given, then we can estimate it(in some cases) by:
where 
population standard deviation
For this case, we're specified that:
- Sample mean = = 2.3
- Sample size = n = 15
- Population mean = = 2.7
- Population standard deviation = = 0.4
Thus, the value of the z-statistic is evaluated as:
Thus, the value of the z statistic for the considered data is given by: Option A: -3.87 approximately.
Learn more about z statistic here:
brainly.com/question/27003351
Answer:
y= x less than 1.5 +4.25
Step-by-step explanation:
Answer:
And we can find this probability with the complement rule:
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".
Solution to the problem
Let X the random variable that represent the average homicide rate for the cities of a population, and for this case we know the distribution for X is given by:
Where 
and 
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability with the complement rule:
