Question 1068667
You need the mean and sd
Add them and divide by 5 and the mean is 122.3
Take the squared differences from 122.3, add them and divide by (5-1) or 4, and then take the square root of that, or 0.4583.
a 95% CI is t df=4 0.975, which you can take from a table (2.776) and multiply it by the std dev (0.4583) and divide by sqrt(5), the sqrt (sample size).  That is the interval width, and it is 0.5690.
The interval is subtracted and added to the mean to get two numbers
(121.7, 122.9)
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What this means is that we do not know the exact melting point of the compound, but we are highly confident that it lies in the above interval.  Stated another way, were we to construct 100 intervals from 100 different samples of 5, the true value would lie in 95 intervals, although we would not know which 95.
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90% confidence is narrower, because we are less confident of the answer, therefore it can be in a narrower interval.  Take the extreme case of complete confidence.  That would require an infinite interval. The higher the confidence, the wider the interval has to be.
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Ho is melting point is 122
Ha is melting point is not 122
alpha is 0.05 
the p-value is 0.22, so it is quite likely we could obtain a result of 122.3 with the true mean's being 122. Such would occur about 1 time in 5, and we generally use 0.05 or less as being a result not due to chance.

Also, the value 122 lies within the 95% confidence interval, therefore, we are highly confident the melting point is 122.