Question 1196104
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σ = greek lowercase letter sigma


Because sigma is unknown and because n < 30, this means we cannot use the Z distribution. We must use the T distribution.


df = degrees of freedom
df = n-1
df = 17-1
df = 16


Then use a reference table like this
<a href = "https://www.sjsu.edu/faculty/gerstman/StatPrimer/t-table.pdf">https://www.sjsu.edu/faculty/gerstman/StatPrimer/t-table.pdf</a>
Locate the df = 16 row
Circle everything in this row.


Then circle the column that corresponds to "two tails =  0.01" whch is the third column from the right.


The row and column intersect at the value  2.921
What this means is P(-2.921 < T < 2.921) = 0.99 approximately when df = 16
This gives us the 99% confidence interval, and the 1% rejection region (aka the significance level)


Answer: Approximately 2.921
Use a specialized statistics calculator to get a more accurate value. 
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