# Confidence interval for mean methods

The association of coffee growers in Puerto Rico wants to know the average pounds of coffee consumption per week in towns in the metropolitan area. In a study conducted recently by the average of 81 persons was 1.5 pounds a week and a standard deviation of 0 .10.

1) What is the value of the average population?

2) What distribution we have to use, z or t?

3) What is the value of t for a confidence level of 95%?

4) Construct a confidence interval of 95% for the population mean.

#### Solution Preview

...a standard deviation of 0 .10.

1) What is the value of the average population?

Estimate of average population = sample mean = 1.5 pounds

2) What distribution we have to use, z or t?

Since population Standard deviation is unknown, the distribution is t

3) What is the ...