Answer:
a)
90% confidence interval for the mean grading time of all composition papers.
(12.47981 , 13.52019)
b)
Appropriate inequality
The interval is ( 12.47981 < μ < 13.52019)
Step-by-step explanation:
<u><em>Explanation</em></u>:-
a)
Given sample size 'n' = 40
Mean of the sample = 13 minutes
standard deviation = 2 min
level of significance = 0.10 or 90%
90% confidence interval for the mean grading time of all composition papers.


( 13 - 0.52019 , 13 + 0.52019)
(12.47981 , 13.52019)
b)
The interval is ( 12.47981 < μ < 13.52019)
I’m not to sure because the picture is blurry
<span>5(1/2x - 2)
Thats what I think.</span>
Normal or natural variations in the quality of production output that are due purely to chance are common causes.
According to the statement
we have to tell about the that cause which effect the quality and production output in the normal and natural variation.
So, For this purpose, we know that the
Common cause variation is present when the control chart of a process measure shows a random pattern of variation with all points within the control limits. When a control chart shows common cause variation, a process measure is said to be in statistical control or stable.
And due to this cause there is a lot of effect on the natural variations in the quality of production output.
So, Normal or natural variations in the quality of production output that are due purely to chance are common causes.
Learn more about common cause variation here
brainly.com/question/28040185
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