Doppler does not always provide a valid estimate of the speed of blood cells because the shift is related to the __________of the angle between the direction of the beam and the direction of blood flow.

Pulsed or continuous spectral Doppler measures _______ velocity. (peak or mean?)

Download the excel file WMT.xlsx which lists monthly stock prices for Walmart since Jun 2015. Use the price column (column B) to compute returns as rt = ln(pt/pt-1) where pt is the adjusted price on month t, and convert the return to percentages (remember this is a log return and times 100). Use this information to compute the following in Questions 1-5.   Please don’t directly use the code in the practice quiz because there are mistakes and typos.

refraction can cause shadowing

skewness of the log return Please report up to 2 significant digits in the decimal. 

Variance mode color maps provide information about blood flow that relates to all of the following except:

Color Doppler measures ____________velocity. (Peak, Mean)

Autocorrelation is a digital computer based technique used to process both pulsed and continuous wave Doppler signals.

A maximum Doppler shift is obtained when the angle between the direction of blood flow and the direction of the sound beam is:

A Reynold’s number greater than 2000 indicaties laminar flow.