The mean for a set of measurements is 4.17 and the standard deviation is 0.14. to show 95% confidence limits, we can write the result of the measurements as 4.17+ -

The 95% confidence level is

Explanation:

If we can apply the central limit theorem, we can approximate this distribution to a normal distribution.

The confidence level (for n=1) is defined as

For a 95% confidence interval, according to the normal distribution, z=1.96.

Then we have:

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  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-