The Mean Length of a Small Counter Balance Bar Is

question 7

Multiple Choice

The mean length of a small counter balance bar is 43 millimeters. There is concern that the adjustments 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 area beyond the critical.
• 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) None of these statements are true

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A preconceived opinion or judgment formed without adequate grounds or before sufficient knowledge.

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The actions or reactions of an individual, usually in relation to the environment, which can be observed and measured externally.

Prejudice

Preconceived opinions or judgments towards people or groups without sufficient knowledge, often based on stereotypes.

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The act of working together with others towards a common goal or purpose.