The average weight of 25 chocolate bars selected from a normally distributed population is 200 grams with a standard deviation of 10 grams.

Question

   The average weight of 25 chocolate bars selected from a normally distributed population is 200 grams with a standard deviation of 10 grams. Find the point estimate and the confidence interval using 95% confidence level.

Are these correct?

https://imgur.com/xnl6BrA

https://imgur.com/Hw81CrU

Answer 1

mean or average + or - 1.96(SD) = 200 + or - 1.96(10 = 200+ or 19.6

area under the normal curve from z=--1.96 to z=+1.96, is 0.95 = 95%

95% confidence interval is (180.4, 219.6)

using a less precise "empirical rule" you'd get (180, 220) Point estimate = 200 grams