A girl wants to count the steps of a moving escalator which is going up. If she is going up on it, she counts 60 steps. If she i
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Answer:
a)
Now we just take square root on both sides of the interval and we got:
b) For this case we are 98% confidence that the true deviation for the population of interest is between 19.08 and 66.56
Step-by-step explanation:
423.6, 487.3, 453.2, 402.9, 483.0, 477.7, 442.3, 418.4, 459.0
Part a
The confidence interval for the population variance is given by the following formula:
On this case we need to find the sample standard deviation with the following formula:
The sample deviation for this case is s=30.23
The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:
The Confidence interval is 0.98 or 98%, the value of and
, and the critical values are:
And replacing into the formula for the interval we got:
Now we just take square root on both sides of the interval and we got:
Part b
For this case we are 98% confidence that the true deviation for the population of interest is between 19.08 and 66.56