A Severe Drought Affected Several Western States for 3 Years

question 112

Multiple Choice

A severe drought affected several western states for 3 years. A Christmas tree farmer is worried about thedroughtʹs effect on the size of his trees. To decide whether the growth of the trees has been retarded, the farmerdecides to take a sample of the heights of 25 trees. Typically trees of this age have a mean height of 65 incheswith a standard deviation of 9 inches. Assuming the distribution is bell shaped, where do you expect middle95% of the tree heights to fall?

• A) between 47 and 83 inches tall
• B) between 56 and 74 inches tall
• C) between 38 and 92 inches tall
• D) over 56 inches tall

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Definitions:

Degrees of Freedom

The number of independent values or quantities which can be assigned to a statistical distribution, typically in the context of parameter estimation.

ANOVA F Test

A statistical method used to determine if there are any statistically significant differences between the means of three or more independent groups.

Standard Deviations

A standard used to assess the level of heterogeneity or diversity among values in a dataset.

Boxplots

A graphical representation of data that shows the distribution's five-number summary: minimum, first quartile, median, third quartile, and maximum.