A scientist counts the number of inclusions in a sample of 30 tourmaline rocks, each of weight 50g.

(a)If the sample mean number of inclusions per gem is 30.7489 and the sample standard deviation of the number of inclusions is 1.1606, calculate the standard error of the mean number of inclusions.

a) = 0.2118

(b)Provide a 95% confidence interval for the mean number of inclusions per tourmaline gem (answer to 4 decimal places).

x bar = 30.7489

T-crit = 2.045

sx = 0.2118

My problem is that 30.7489 2.045 * (0.2118) is not giving me a correct outcome.

I have tried submitting 30.3158, 31.1820 but it is incorrect.