A phone company offers two monthly plans. Plan A costs $10 plus an additional $0.15 for each minute of calls. Plan B costs $19 p
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From the data given, we estimate the population mean and population standard deviation. Then, we use this estimate to find a 95% confidence interval for the population variance and the population standard deviation.
Sample:
Salaries in millions of dollars: 2.2, 1.5, 0.5, 1.3, 2.4, 1.5, 2.7, 0.3, 2.0, 0.3
Question a:
The mean is the sum of all values divided by the number of values. So
The sample mean salary is of 1.42 million.
Question b:
The standard deviation is the square root of the difference squared between each value and the mean, divided by one less than the number of values.
So
Thus, the estimate for the population standard deviation is of 0.8772 million.
Question c:
The sample size is
The significance level is
The estimate, which is the sample standard deviation, is of .
Now, we have to find the critical values for the Pearson distribution. They are:
The confidence interval for the population variance is:
Thus, the 95% confidence interval for the population variance is (0.3641, 2.5646)
Question d:
Standard deviation is the square root of variance, so:
The 95% confidence interval for the population standard deviation is (0.6034, 1.6014).
For more on confidence intervals for population mean/standard deviation, you can check brainly.com/question/13807706