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Null Hypothesis

1)According to company figures, the age of a first time customer is normally distributed with an average age of 29.8 years and a standard deviation of 4.5 years. The marketing department has designed a new advertising strategy and wants to determine if this has had any impact on the average viewing age. Since the new ad campaign began, sales have been made to 64 new customers whose average age is 31.1 years. Testing at the 5% level of significance, has the new campaign had any impact?

Complete the following

H0:  =

H1: 

Alpha =

St. error =

n =

sample mean =

Calculations leading to your conclusion:

Final answer:


3) A package delivery company frequently makes trips to a small neighboring community. There are two roads to the other town, Highway A and Route B. Since time is money for the company, the manager wants to know if there is a significant difference in the average time it takes to make a round trip to the neighboring community. After testing each road 36 times, the following statistics were collected:

Highway A Route B
Mean 18 20
Sample Dev. 5.3 10
Size 36 36

Test the hypothesis that there is not a significant time difference between the two options at the 5% level of significance.

p-value =



4)A sample of 200 customers at a local establishment revealed that the mean age of the group was 25.4 years with a standard deviation of 10 years.

a)Determine the 95% confidence interval for the true mean of the customers.

From ____________ to ____________ years of age

b) Determine the 99% confidence interval for the true mean of the customers.

From ____________ to ____________ years of age