Here are returns and standard deviations for four investments.

	Return (%)	Standard Deviation (%)
Treasury bills	5.0	0
Stock P	11.5	16
Stock Q	14.5	28
Stock R	24.0	27

Calculate the standard deviations of the following portfolios.

a. 50% in Treasury bills, 50% in stock P. (Enter your answer as a percent rounded to 2 decimal places.)

a.Standart Deviation:?%

b. 50% each in Q and R, assuming the shares have: (Do not round intermediate calculations. Enter your answers as a percent rounded to 2 decimal places.)

b.

Perfect positive correlation standart deviation:?%

Perfect negative correlation standart deviation:?%

No correlation standart deviation:?%