The mean and standard deviation height (in cms) for fifty girls in year 10 at a particular School are 164.3 and 7.49 respectively. The mean height for thirty-six boys is 173.5 cm. If 4 boys of the 36 boys in year 10, are shorter than the mean height for girls find the Standard deviation of the boys’ heights. Assume all heights are normally distribute

Question

The mean and standard deviation height (in cms) for fifty girls in year 10 at a particular School are 164.3 and 7.49 respectively. The mean height for thirty-six boys is 173.5 cm.  If 4 boys of the 36 boys in year 10, are shorter than the mean height for girls find the Standard deviation of the boys’ heights. Assume all heights are normally distribute

amistre64 · Answer

4/36 = 1/9 = 0.11111; or about 11.11%

if im recalling this right

amistre64 · Answer

164.3 - 173.5
------------- = zscore that has a percentage of 11.11%
        sd

amistre64 · Answer

would need to find a ztable, or a calculator that can determine the zscore.  Ill look on a table from google ...

zscore for .1111 = -1.22 seems best

sd for boys = (164.3-173.5)/-1.22 = abt 7.45