What part of the problem is giving you pause? Theres not a whole lot of background, so don't really know how much to go into this problem.
An exporter of Ginseng Tea claims that the average weight of packets
of Ginseng Tea is 20 g. A random sample of 36 packets of ginseng tea
was collected. From the sample, the average weight was calculated as
19.35 g. The population standard deviation of the weights is known to
be 1.8 g. The weights are normally distributed.
i. Calculate the 95% confidence interval for the population average
weight.
ii. Estimate the range for the total weight of 50 randomly selected packets of Ginseng tea with 95% confidence.
(i)
Sample mean = 19.35
Standard deviation = 1.8
Standard error of mean = σ / √ n
Standard error of mean = 1.8 / √ 36
SE = 1.8/6
Standard error of mean 0.3
Confidence interval 19.35-(0.3)(1.96)
and 19.35+(0.3)(1.96)
95 % confidence interval is (18.762, 19.938)
(ii)Sample mean = 19.35
Standard deviation = 1.8
Standard error of mean = σ / √ n
Standard error of mean = 1.8 / √ 50
SE = 1.8/7.1
Standard error of mean 0.25
Confidence interval 19.35-(0.25)(1.96)
and 19.35+(0.25)(1.96)
95 % confidence interval is (18.86, 19.84)
Hows this?