SAT Math: Data Analysis

Descriptive Statistics

What is the average of all the integers from 1 to 348, inclusive?

A.  116

B.  173.5

C.  174

D.  174.5

E.  238.5

Knowsys Method

Read the question carefully.  Make sure you know all of the relevant vocabulary.  For example, an integer is a whole number rather than a fraction or a decimal.

Identify the bottom line.  Make a note on your paper to remind you to find the average: avg = ?

Assess your options.  Your Knowsys handbook has a quick and easy method for solving this type of problem.  To find the average of sequential, evenly-spaced numbers: average the extremes (the biggest number and the smallest number).

Attack the problem.  You know that an average is the sum of the numbers divided by the number of the numbers.  In this problem you have 1 and 348.  Use the same method of adding them up and then dividing them by the number of the numbers (2).

1 + 348 = 349.          (Now you must divide to find the average of these two numbers.)

349 / 2 = 174.5

Loop back.  You followed the method for finding the average of sequential, evenly-spaced numbers.  Look down at your answer choices.