# Question: With reference to Exercise 11 36 construct a 90 confidence interval

With reference to Exercise 11.36, construct a 90% confidence interval for the ratio of the variances of the two populations sampled.

In exercise

The following are the heat- producing capacities of coal from two mines (in millions of calories per ton):

Assuming that the data constitute independent random samples from normal populations with equal variances, construct a 99% confidence interval for the difference between the true average heat-producing capacities of coal from the two mines.

In exercise

The following are the heat- producing capacities of coal from two mines (in millions of calories per ton):

Assuming that the data constitute independent random samples from normal populations with equal variances, construct a 99% confidence interval for the difference between the true average heat-producing capacities of coal from the two mines.

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