Michael baked 60 oatmeal cookies and 45 chocolate chip cookies to package in plastic containers for her friends at school. She w
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Answer:
Step-by-step explanation:
We are given the following in the question:
Sample size, n = 67
Variance = 3.85
We have to find 80% confidence interval for the population variance of the weights.
Degree of freedom = 67 - 1 = 66
Level of significance = 0.2
Chi square critical value for lower tail =
Chi square critical value for upper tail =
80% confidence interval:
Putting values, we get,
Thus, (3.13,4.91) is the required 80% confidence interval for the population variance of the weights.