Question

1.Express the confidence interval (168.9,309.7)(168.9,309.7) in the form of ¯x±MEx¯±ME.

¯x±ME

2.A quality control company was hired to study the length of meter sticks produced by a certain company. The team carefully measured the length of many many meter sticks, and the distribution seems to be slightly skewed to the right with a mean of 100.03 cm and a standard deviation of 0.13 cm.

a) What is the probability of finding a meter stick with a length of more than 100.12 cm

b) What is the probability of finding a group of 22 meter sticks with a mean length of less than 100 cm?

c) What is the probability of finding a group of 34 meter sticks with a mean length of more than 100.06 cm?

d) What is the probability of finding a group of 44 meter sticks with a mean length of between 100.02 and 100.05 cm?

e) For a random sample of 50 meter sticks, what mean length would be at the 92nd percentile?

3.We wish to estimate what percent of adult residents in a certain county are parents. Out of 400 adult residents sampled, 216 had kids. Based on this, construct a 90% confidence interval for the proportion ππ of adult residents who are parents in this county.

Give your answers as decimals, to three places.

_____< ππ <____

Answer 1

1. Here (168.9,309.7)

So sample mean is

And Margin of Error is

So answer here is