The Mean Length of a Small Counter Balance Bar Is

question 84

Multiple Choice

The mean length of a small counter balance bar is 43 millimeters. There is concern that the settings of the machine producing the bars have changed. Test the claim at the 0.02 level that there has been no change in the mean length. The alternate hypothesis is that there has been a change. Twelve bars (n = 12) were selected at random and their lengths recorded. The lengths are (in millimeters) 42, 39, 42, 45, 43, 40, 39, 41, 40, 42, 43 and 42. The mean of the sample is 41.5 and the standard deviation 1.784. Computed t = -2.913. Has there been a statistically significant change in the mean length of the bars?

• A) Yes, because the computed t lies in the rejection region.
• B) No, because the information given is not complete.
• C) No, because the computed t lies in the area to the right of -2.718.
• D) Yes, because 43 is greater than 41.5.

---

Definitions:

Equilibrium Quantity

At the market equilibrium price, the amount of goods or services that are supplied matches the amount that is demanded.

Equilibrium Price

A pricing point in the market where the supply of goods meets the demand for those goods.

Equilibrium Quantity

The quantity of goods or services that is supplied and demanded at the equilibrium price, where supply equals demand in a market.

Equilibrium Price

The cost at which the amount of products offered matches the amount of products requested.