Confidence Interval for Wind Speed in the Republic of Ireland

In this activity, you will be calculating the 95% confidence interval for the daily wind speed in the Republic of Ireland from 1961-1978. The data is a random sample from a data set containing over 74,000 points.

Using the data set in Excel, determine the mean and standard deviation for the daily wind speed. Then calculate the 95% confidence interval.

1. What is the mean?
2. What is the standard deviation?
3. What is the 95% confidence interval?
Would the confidence interval become wider or more narrow, if the confidence level was 90%?
5. What is the primary reason that the interval is the width that it is?

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