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The ages of members of a policy action group are normally distributed with a mean of 33 years and a standard deviation of 2 years.

There are 400 members in the group 

About how many members are expected to be between 29 years old and 37 years old?

 

272

290

354

380

 Apr 4, 2019
 #1
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Use z-score tables to find out how many are less than 37.....then use table to find out how many are less than 29       subtract the #37 - #29

 

37   is 2 Standard deviations ABOVE 33     z score 2   corresponds to .9772

29   is 2 standard deviations BELOW 33     z score -2  corresponds to .0228

 

(.9772 - .0228) 400 = ~ 382     or     380 members

 Apr 4, 2019

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