Statistics 106 - Quiz 10

To work as a flight attendant for United Airlines, you must be between 5'2" and 6' tall. (source:www.ual.com). The height of 20- to 29-year-old males has a mean of 70.4" and a standard deviation of 3". The height of 20- to 29-year-old females has a mean of 65.1" and a standard deviation of 2.6". A random sample of 500 20- to 29-year-old people from the Midwest and 350 20- to 29-year-old people from the Northeast found that 82 from the Midwest and 65 from the Northeast did not meet the height requirement to work as a flight attendant.

How large, if any, is the difference between the proportion of people from the Midwest States and those in the Northeastern states who are eligible to work as United Airlines flight attendants.

1) The sample percentage difference between the Midwest and Northeast is 0.0217 with a standard error of 0.0265. Calculate the confidence interval with 95% confidence.

2) Explain / justify your conclusions about the hypotheses:

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A study of 66,831 dairy cows found that the mean milk yield was 12.5 kg per milking with a standard deviation of 4.3 kg per milking (data from Berry, et al., 2013). Construct a 95% confidence interval for the average milk yield in the population.

Berry, D. P., Coyne, J., Boughlan, B., Burke, M., McCarthy, J., Enright, B., Cromie, A. R., McParland, S. (2013). Genetics of milking characteristics in dairy cows. Animal, 7(11), 1750-1758.

3) Compute the standard error

4) Compute df

5) Find the multiplier: t*

6) Determine the confidence interval

7) Write a conclusion