Manhattan Review Statistics

Statistics Suppose a set of numbers S= {-2, 0, 3, 3, 21} The average or arithmetic mean of S is The median (middle element) of S is The mode (most common element) of S is The range (greatest difference between any two elements) of S is The standard deviation  is a measure of how far, on average, the elements differ from the arithmetic mean. In other words, the standard deviation measures disperson. 2 

( x1  X ) 2  ( x2  X ) 2  ...( xn  X ) 2 n

, where

X  mean

If the element 5 were added to S , which of the above statistics would change? If the element 0 were added to S , which of the above statistics would change? If each element in S were increased by 2, which of the above statistics would change? If T={ 4, 8, 12, 16, 20, 24, 28, 32 } the median is ______ and the arithmetic mean is ______.

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Is the range of a set of four different even integers less than 8? (1) The product of the four integers is negative. (2) All four integers have two digits.

A team of 7 salespeople sold an average of 10 flats each last month. Did the youngest member sell at least one flat last month? (1) The oldest salesperson sold 15 flats, more than any other salesperson. (2) The median number of flats that each salesperson sold last month was 8.

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167 160

159 165

164 149

181 170

174 152

Above are the heights in centimeters of 10 women from a country where the average height of women is 160 cm and the standard deviation is 6 cm. What fraction of these women have a height that is within 2.5 standard deviations of the mean? 5/10

6/10

7/10

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8/10

9/10

Orange (GMAT Review 11th Edition) PS (Problem Solving) 65,68,93,201,204,208,212,215,218 DS (Data Sufficiency) 104 Green (GMAT Quantitative Review) PS (Problem Solving) 59,63,70,148,161 DS (Data Sufficiency) 34,40

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