Respuesta :
Answer:
Step-by-step explanation:
This question can be solved by the knowledge of normal distribution and z-score
what is normal distribution?
Normal distribution is a curve plotted when a symmetrical data set is plotted on a graph with freqency on y-axis and data values on x-axis.
It is a bell shaped curve
What is z-score?
It is given by the formula:
[tex]z=\frac{|x-\mu|}{\sigma}[/tex]
where x is the value whose z score is to be computed, [tex]\mu[/tex] is is the population mean and [tex]\sigma[/tex] is the standard deviation.
a) To calculate centiles one must refer to the Z table
In the z table search for value just greater than .17
So for .17 the z-score is -0.95
Now the value can be computed by the formula
[tex]x=\mu+z\sigma[/tex]
As per question, [tex]\mu[/tex] = 23 and [tex]\sigma[/tex] = 1
x = 23 + (-0.95)*1
x= 22.05
So the The 17th percentile for incubation times is 22 days.
b) T calculate middle 97% we must find the values corresponding to 1.5% and 98.5%. Using the z table, we find that for 1.5% z = -2.97 and 98.5% z=+2.97
Therefore by using the same formula as in (a)
[tex]x=\mu+z\sigma[/tex]
x = 23 + (±2.97)*1
x= 20.03 and 25.97
So The incubation times that make up the middle 97% are 20 to 26 days.
earn more about z tables here https://brainly.com/question/7001627
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