The Mean Length of a Candy Bar Is 43 Millimeters

question 42

Multiple Choice

The mean length of a candy bar is 43 millimeters. There is concern that the settings of the machine
Cutting 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. 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:

Standard Error of Estimate

It measures the accuracy with which a sample represents a population, specifically the standard deviation of the observed values from the values predicted by a regression model.

Significance Level

The likelihood of incorrectly dismissing the null hypothesis during a statistical test when it is in fact correct; an assessment of the chance of committing a Type I error.

Negatively Linearly Related

A relationship between two variables where an increase in one variable results in a decrease in the other, represented by a downward sloping line on a graph.

Linear Relationship

A linear relationship describes a straight-line relationship between two variables, where a change in one variable is proportional to a change in the other.