Here are returns and standard deviations for four investments.

	Return (%)	Standard Deviation (%)
Treasury bills	4.0	0
Stock P	12.0	10
Stock Q	16.5	25
Stock R	23.5	26

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.)

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.)

	Standard Deviation
Perfect positive correlation		%
Perfect negative correlation		%
No correlation		%