Jane is collecting stamps. He has 57 pages of stamps with an average of 30 stamps per page. If the average selling price of each
1 answer:
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NOTE:
As Part (a) and Part (b) are already correctly solved in the question, I will be solving Part (c), Part (d) and Part (e).
Answer:
Part (c):
As we are not given the standard deviation of the population, we will use
t-distribution for this scenario.
The degrees of freedom will be n-1 = 80, hence our distribution parameter will be t.
Part (d):
The critical value (t) for 95% confidence level is at 80 degree of freedom is obtained from the attached table.
t = 1.99
Now, let us first calculate the error bound
E = t * (sx)/(√n)
E = 1.99 * (4)/(√81)
E = 0.884 ===========> Error Bound
Confidence interval is obtained as follows:
(X¯ - E), (X¯ + E)
(8 - 0.884), (8 + 0.884)
(7.116, 8.884) ===========> Confidence Interval
Graph is attached as an image.
Part (e):
The confidence interval indicates that we can predict with 95% confidence that the population mean time wasted at the court, waiting to be called for jury duty, will lie between 7.1155 and 8.8845 hours.
