A Type II error is failing to reject H when H is in fact false. In terms of the problem this says-
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going along with the length of the rods produced by Machine A is equal to 90 cm (fail to reject H : u = 90)
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when in fact the length of the rods is not 90 cm (H : u = 90 is false).
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The NAIRU determines when an economy will experience bottlenecks in the labor market.

As the economy expands, the risk of default due to improving cash flows would diminish and reduce the spread between higher rated and lower rated bonds.

Such an index weights each country in the overall index in proportion to its relative GDP.

Excess reserves are actual reserves that exceed the legal requirement.