Question

NMUPS = Nonmedical Use of Prescription Stimulants
SE = Study Enhancement

Research Method: Total of 15 098 US students surveyed (2009-2015) and divided into 4 subgroups: (1) no past-year NMUPS (nonusers), (2) past-year NMUPS to help study (NMUPS-SE only), (3) past-year NMUPS for study/ nonstudy motives (NMUPS-SEþ other), and (4) past-year NMUPS for nonstudy motives (NMUPS-nonSE only). Student characteristics (eg, grade point average [GPA]) and substance-related problems (eg, binge drinking) compared between subgroups.

1. Define the following terms

1. F statistic
2. Weighted estimate. Explain how it applies in this study.

Answer 1

A) The F-statistic is simply a ratio of two variances.

The following is an equation commonly used to compute an f statistic:

f = [ s12/σ12 ] / [ s22/σ22 ]

where σ1 is the standard deviation of population 1, s1 is the standard deviation of the sample drawn from population 1, σ2 is the standard deviation of population 2, and s1 is the standard deviation of the sample drawn from population 2.

B)

Weighted average is a calculation that takes into account the varying degrees of importance of the numbers in a data set. In calculating a weighted average, each number in the data set is multiplied by a predetermined weight before the final calculation is made.

This can be used in this study , as this different groups have diffrent weights.