Question

1. Estimate, with 95% confidence, the percent of all end-users in South America in 2014 that were not dissatisfied  i.e. they responded with 3, 4, or 5 ?  Clearly interpret your interval.

South America
year / Score	0	1	2	3	4	5	Total
2010	1	2	5	18	36	38	100
2011	1	3	6	17	36	37	100
2012	0	2	6	19	37	36	100
2013	0	2	5	20	37	36	100
2014	0	2	5	19	37	37	100

Thank you,

Answer 1

The data is:

19, 37 & 37

Mean of the data =

The standard deviation of the data =

The critical t-value for and df = 2 is 4.30

The 95% confidence interval is:

= 31 4.30*

= 5.184, 56.816

The 95% confidence interval of the percent of all end-users in South America in 2014 that were not dissatisfied is between 5.184 and 56.816.

We are 95% confident that the percent of all end-users in South America in 2014 that were not dissatisfied is between 5.184 and 56.816.