[R] mixtools? Fitting two-normal distributions to data where one of the two normal distributions (the one corresponding to lower values of x) is a left-truncated normal distribution.

[John Sorkin]

I am trying to model the mixture of two normal distributions, where x values are in the range of zero to some positive value. I know about mixtools and would use it save for the fact that the the y values from the normal distribution corresponding to the lower values of x (i.e. from zero to x/n) are from what appears to be a left-truncated normal distribution (i.e. the y values are all from the upper half of a normal distribution). The y values from higher values of x (i.e. from x/n to x) all appear to come from a normal distribution. Can someone suggest how to fit two normal distributions where one of the two distributions is left-truncated? Can this be done using mixtools?
Thank you,
John 

John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing) 


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