![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
The random sample size is![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=8b1560b238d7a8afce1d46eff68b99bf.png\")
.
The results is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=9033a4d7ab09bf88efc49d3f50a11f09.png\")
.
The confidence level is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=f613fc58230f73c43d646c5467c64e75.png\")
.
Find the standard deviation.
\The formula for maximum error of estimate is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=c2ac75e9508a11b5e365758149076ff3.png\")
.
The confidence level corresponds to ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=ac1b8b6fce7d2c5ab4032ca31b3d3514.png\")
score, thus ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=fa2a2004401871808e4b74475388ae52.png\")
.
Substitute all the values.
\![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=f75ed5c5c7e42d5da1918c9910f58d69.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=eca36ef76a0bf90a160c5b337168d8d3.png\")
The standard deviation is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5567f8109e4096ce28cb7f677c00cdfe.png\")
.
![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
The standard deviation is ![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5567f8109e4096ce28cb7f677c00cdfe.png\")
. \ \